Before you call a repair shop

Free computer health check. Find out what's wrong and fix it.

Try this before paying someone. Step-by-step fixes for common PC problems, in plain English. Everything runs on your device. Nothing is uploaded.

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About CalmPC & all 75 fix guides

Free computer troubleshooting guides for Windows, Mac, and Linux

CalmPC is a free, browser-based tool that runs a health check on your computer and walks you through fixing problems yourself, step by step, in plain English. No technical knowledge needed. Nothing is downloaded or uploaded. Everything runs on your device.

The health check tests your computer's performance, browser compatibility, internet connection speed, and camera and microphone permissions. You get an instant health score with specific fixes for anything that needs attention. Guides cover Windows 10 and 11, macOS, and common Linux distributions.

The built-in network speed test measures ping (your connection's response time in milliseconds) and download speed in Mbps using Cloudflare's servers. Nothing is uploaded. Your result is rated fast, average, or slow, and if your connection needs attention the health check links you straight to the relevant fix guide. The test runs entirely in your browser with no account, no install, and no data leaving your device.

Speed & Performance

  • Computer running slow: restart properly, check Task Manager, power plan, disk space, SFC scan, thermal throttling
  • App keeps crashing: Event Viewer diagnosis, Visual C++ Redistributables, AppData cleanup, run as administrator
  • Running out of storage space: Disk Cleanup, Windows.old folder, hiberfil.sys, TreeSize Free, Temp folder
  • 100% disk usage: Resource Monitor to find culprit, disable SysMain, CrystalDiskInfo SMART check, Delivery Optimization, pagefile settings
  • Blue Screen of Death (BSOD): stop code lookup, GPU driver rollback, RAM test with mdsched and Memtest86, SFC and DISM, HWiNFO64 temperature check
  • Right-click menu not working: Explorer.exe restart, ShellExView shell extension audit, SFC scan, clean boot, Windows 11 context menu fix
  • Computer keeps restarting: Kernel-Power 41 in Event Viewer, Windows Update active hours, thermal shutdown diagnosis with HWiNFO64, disable auto-restart to reveal BSOD stop code, RAM test with mdsched, SFC and DISM, PSU fault diagnosis
  • Game lag, FPS drops, and stuttering: FPS counter to separate from network lag, Windows Game Mode, disable Xbox background recording, close bandwidth hogs, HWiNFO64 temperature check for thermal throttling, High Performance power plan, monitor refresh rate match, verify game files in Steam or Epic
  • Start Menu or Taskbar not working (Windows 11): Windows Explorer restart in Task Manager, pending Windows Update check, PowerShell ShellExperienceHost re-registration, new user account test, SFC scan, DISM RestoreHealth, uninstall problematic update, Reset this PC with Keep my files
  • Windows Search not working: Windows Search service restart in services.msc, Search and Indexing troubleshooter, index rebuild in Control Panel Indexing Options, PowerShell Windows Search app re-registration, Group Policy registry check, SFC scan, Windows Update
  • Copy and paste not working: Windows Explorer restart, rdpclip.exe restart, Clipboard history clear, find clipboard-locking app, Group Policy Clipboard redirection check, SFC scan, remove third-party clipboard managers, app-specific clipboard settings
  • Game won't launch: read the error message first (DLL, DirectX, anti-cheat), install Visual C++ Redistributables and DirectX End-User Runtime, verify game files in Steam or Epic, run as administrator, add game folder to antivirus exclusions, repair Easy Anti-Cheat or BattlEye from game folder, Event Viewer faulting module lookup for silent crashes

Internet & Browser

  • Slow or no internet: router restart, 2.4GHz vs 5GHz, DNS to 1.1.1.1, netsh winsock reset, ISP throttling test
  • Browser won't load pages: Private window test, proxy settings, DNS flush, SSL certificate issues, extensions
  • Browser needs updating: Chrome, Edge, and Firefox update guides, enterprise-managed browser scenarios
  • Wi-Fi keeps disconnecting: adapter power management, driver update, roaming aggressiveness, forget and reconnect, 2.4GHz vs 5GHz band, router firmware
  • High ping while gaming: confirm FPS vs network lag, switch to Ethernet, close background bandwidth users, correct game server region, DNS to 1.1.1.1, QoS on router, router and modem reboot, ISP routing test with WinMTR
  • WiFi won't connect or no networks found: Device Manager adapter check, Airplane Mode toggle, forget and reconnect network, netsh winsock reset and ipconfig /flushdns, update or roll back WiFi driver, disable power management on adapter, network troubleshooter, full network reset
  • VPN not connecting: Remote Access Connection Manager and SSTP service check in services.msc, uninstall and clean reinstall with TAP and WireGuard adapter removal from Device Manager, delete and recreate the VPN profile, netsh winsock reset, firewall exception for the VPN executable, switch VPN protocol (OpenVPN TCP 443 bypasses most blocks), mobile hotspot test for ISP blocking

Sound & Display

  • Sound not working: output device, audio enhancements, exclusive control, Volume Mixer, driver reinstall
  • Microphone not working: physical mute button and LED, correct input device selection, two-layer Windows microphone privacy settings, app-level mic selector in Teams/Zoom/Discord, microphone boost levels, audio driver reinstall
  • Screen frozen or unresponsive: GPU driver reset shortcut, Event Viewer, Fast Startup, RAM test with Memtest86
  • Screen flickering: Task Manager flicker test to isolate cause, GPU driver rollback with DDU, refresh rate, display cable, hardware acceleration, shell extension conflicts
  • Second monitor not detected: GPU port vs motherboard port, Windows + P projection, Detect button, cable swap, GPU driver update

Security & Access

  • Virus or malware warning: spot real vs scam alerts, Windows Defender Offline scan, Malwarebytes, ESET Online Scanner
  • Pop-ups and annoying ads: browser notifications, extension adware, shortcut hijacking, AdwCleaner, uBlock Origin
  • Can't log in: Caps Lock, keyboard layout, PIN vs password, Credential Manager, Safe Mode recovery
  • Windows not activated: Activation Troubleshooter, link to Microsoft account, slmgr /ato, phone activation via slui 4, invalid third-party key warning
  • Windows Hello not working (fingerprint or face): check enrollment in Sign-in options, remove and re-enroll biometrics, update biometric driver in Device Manager, download manufacturer driver (Dell, Lenovo, HP, ASUS), Windows Biometric Service check in services.msc, Group Policy biometrics policy check, Windows Hello PIN reset and re-enroll, optional driver updates in Windows Update
  • Browser notification spam: find allowed notification sites in chrome://settings/content/notifications or about:preferences#privacy, remove unrecognised entries, set default to block all future requests, check clipboard-read access, enable Chrome quieter messaging to silence prompts without blocking entirely
  • Unknown background browser scripts (service workers): open F12 DevTools, Application tab, Service workers in Chrome or Edge to see installed workers, Unregister anything unrecognised, use Storage section to clear all site data for suspicious origins, Firefox equivalent at about:debugging, full clear with chrome://settings/clearBrowserData as last resort

Hardware & Devices

  • Computer making strange noises: CrystalDiskInfo SMART check, clicking drive backup warning, coil whine, fan noise, beep codes
  • Printer not working: Print Spooler restart, spool folder clear, Wi-Fi reconnection, manufacturer driver install
  • Laptop battery draining too fast: powercfg batteryreport, sleepstudy, power modes, lithium battery health
  • USB device not recognized: back-panel ports, Device Manager errors, USB Selective Suspend, reinstall USB controllers, powered hub for external drives
  • Bluetooth not connecting: remove and re-pair, pairing mode, Bluetooth Support Service, driver update, USB 3.0 interference fix
  • Keyboard or mouse stops working: USB Selective Suspend, USB Root Hub power management, back-panel ports, wireless receiver interference, HID driver update
  • Webcam not working: physical privacy shutter, camera privacy settings, close competing apps, Windows Camera app test, driver reinstall
  • Computer won't turn on: power and monitor cable check, capacitor drain, beep codes, RAM reseating, GPU removal test, Safe Mode
  • Laptop running hot or overheating: hard flat surface and unblocked vents, HWiNFO64 temperature monitoring, background CPU culprit in Task Manager, Balanced power plan, compressed air vent cleaning, cooling pad, thermal paste replacement for older laptops
  • Laptop not charging: cable and brick test, wattage match check, OEM battery conservation mode (Dell Command, Lenovo Vantage, MyASUS, HP Smart), powercfg /batteryreport design vs full charge capacity, ACPI battery driver reinstall in Device Manager, charging port cleaning, BIOS update, direct outlet test
  • GPU driver crash or display driver error: Event Viewer nvlddmkm/amdkmdag source confirmation, HWiNFO64 temperature check, DDU from Guru3D download, driver download before Safe Mode, DDU clean removal in Safe Mode, custom clean installation of new driver, FurMark load test
  • PC black screen with no display: GPU port vs motherboard port, cable and port swap, Fast Startup disable, Win+Ctrl+Shift+B display driver reset, Safe Mode isolation, GPU driver roll back with DDU, RAM reseating, POST beep code diagnosis
  • Laptop touchpad not working: Fn key touchpad toggle, external mouse disconnection, Settings touchpad toggle, driver disable/enable cycle in Device Manager, manufacturer driver from support site, driver roll back, BIOS update, Hardware and Devices troubleshooter (msdt.exe -id DeviceDiagnostic)
  • PC won't sleep or keeps waking: powercfg /requests to find sleep blockers, powercfg /lastwake to find wake source, USB device wake power management, network adapter Wake on Magic Packet, Win+Ctrl+Shift+B for black screen after wake, Fast Startup disable, chipset driver update, Windows Update for sleep regression patches
  • External hard drive or USB drive not showing up: Disk Management vs File Explorer distinction, drive letter assignment, New Simple Volume for unallocated drives, HFS+ format incompatibility with Windows, back-panel port and cable swap, USB and storage controller driver update, BIOS detection check, chkdsk /f /r for bad sectors
  • SSD or hard drive not detected: BIOS storage section check first, SATA cable and power connector swap, M.2 slot protocol compatibility (NVMe vs SATA M.2) in motherboard manual, M.2 and SATA port sharing conflicts, Disk Management initialization for unformatted drives, storage controller driver update from motherboard manufacturer, CrystalDiskInfo SMART health check for reallocated sectors

Files & Updates

  • Accidentally deleted a file: Recycle Bin, Ctrl+Z undo, Previous Versions, cloud trash, Recuva recovery tool, SSD TRIM warning
  • Windows Update stuck or failing: date/time sync, DISM RestoreHealth, Update component reset, Update Assistant
  • Windows 10 end of support: what October 2025 end of support means, PC Health Check compatibility tool, free upgrade path to Windows 11 via Windows Update or Installation Assistant, options for incompatible PCs (Ubuntu Linux, replacement PC), file backup with File History and cloud storage
  • Outlook or email not working: Working Offline, Credential Manager, Outbox jam, scanpst.exe repair, app passwords for 2FA
  • OneDrive not syncing: status icon error messages (red X vs yellow triangle), storage quota check (5 GB free limit), invalid file character fix (* : < > ? / \ |), pause and resume sync, sign out and Unlink this PC to clear auth tokens, onedrive.exe /reset to rebuild sync database, Microsoft Store OneDrive update, Choose folders sync selection check

Mac: Speed & Performance

  • Mac running slow: proper restart with Login Items unticked, Activity Monitor CPU tab (mds_stores reindexing, kernel_task as thermal throttling symptom, WindowServer), Memory Pressure graph (red means disk swap), Login Items cleanup for Ventura and older macOS, storage space check, Safe Mode test to isolate third-party software, SMC reset on Intel Macs
  • Mac storage full: Storage Management breakdown (System Data category), empty Trash plus Photos and iMovie app-specific trash, Downloads folder sorted by size, Time Machine local snapshots with tmutil deletelocalsnapshots (10-50 GB hidden), iPhone and iPad backups in MobileSync/Backup, Optimise Storage, OmniDiskSweeper for hidden large files, Xcode derived data and simulator runtimes, Homebrew and npm cache cleanup
  • Mac overheating or fan running loud: Activity Monitor CPU tab for mds_stores, kernel_task, and Chrome Helper processes, hard flat surface and unblocked hinge vents, switch from Chrome to Safari (reduces idle CPU 20-40%), kill backupd and accountsd runaway processes, SMC reset on Intel Macs to recalibrate fan curves, compressed air for older Mac vents, Stats app for actual CPU temperature monitoring
  • Mac app keeps crashing or won't open: Force quit with Command+Option+Esc and wait 10 seconds, App Store and developer website updates, delete com.company.appname.plist from ~/Library/Preferences, delete Application Support folder for cached data, read crash log in Console app (Crash Reports section) for Exception Type and Faulting module, clean reinstall from App Store or developer website

Mac: Internet & Sound

  • Mac WiFi not working: ping test to isolate DNS from connection (ping 8.8.8.8 vs ping google.com), toggle WiFi off and on, forget network and reconnect for fresh DHCP, DNS to 1.1.1.1 via System Settings, DHCP lease renewal (169.254 self-assigned address means router unreachable), Wireless Diagnostics via Option+click on WiFi icon, delete corrupted preference files in /Library/Preferences/SystemConfiguration/, Keychain Access to remove stale WiFi password
  • No sound on Mac: check output device in System Settings (macOS switches silently to HDMI or Bluetooth), Bluetooth still set as active output after headphone use, stuck headphone jack sensor (plug and unplug wired headphones), Audio MIDI Setup sample rate (44100 Hz or 48000 Hz), restart Core Audio with sudo killall coreaudiod, app-specific audio selectors in Zoom and Discord, Safe Mode to rule out third-party audio extensions like Boom 3D or BlackHole
  • Mac Bluetooth not connecting: toggle Bluetooth off and on, remove and re-pair the device from System Settings Bluetooth, Option+Shift click Bluetooth icon then Debug, Reset the Bluetooth module, delete com.apple.Bluetooth.plist from /Library/Preferences, switch WiFi to 5 GHz to reduce 2.4 GHz interference, move USB 3.0 hubs away from Mac, install pending macOS updates
  • AirDrop not working: confirm WiFi and Bluetooth both active on both devices, set AirDrop to Everyone in Finder Go AirDrop, wake and unlock receiving device, turn off Personal Hotspot on iPhone, uncheck Block all incoming connections in Mac Firewall settings, disable active Focus modes on receiving device, relaunch Finder with Option right-click on Dock icon

Mac: Display

  • Mac screen flickering: try a different cable and connect directly without a hub for external displays, disable Automatic graphics switching in Battery Options on Intel dual-GPU MacBook Pros, disable True Tone in System Settings Displays, switch ProMotion to fixed 60Hz refresh rate on MacBook Pro 2021 and later, Safe Mode to isolate third-party display extensions like BetterDisplay, NVRAM reset on Intel Macs with Command+Option+P+R, Apple Diagnostics with D key for hardware fault codes

Mac: Hardware

  • MacBook not charging: check MagSafe amber or green light, try a different cable (most common cause), match charger wattage to Mac in System Report Power section, disable Optimized Battery Charging in System Settings Battery, clean port with wooden toothpick, SMC reset on Intel Macs with Shift+Control+Option+Power for 10 seconds, check battery cycle count and Condition in System Information Power
  • Mac battery draining too fast: Activity Monitor Energy tab (Energy Impact and 12 hr Power columns), lower screen brightness (biggest single drain), quit Chrome and Electron apps, disable Bluetooth and Location Services when unused, check battery Condition via Option+click on battery icon, enable Low Power Mode, battery cycle count over 1000 and Service Recommended condition means replacement needed
  • Mac camera not working: green LED status (hardware indicator cannot be faked), two-level macOS Camera Privacy settings (master toggle and per-app toggle), only one app can use camera at a time so quit all video apps, Photo Booth test to isolate app vs system fault, sudo killall VDCAssistant to restart camera daemon, NVRAM reset on Intel Macs with Option+Command+P+R, macOS Software Update for camera driver fixes
  • Mac printer not working: remove and re-add printer in System Settings Printers and Scanners, clear stuck jobs in Print Queue with Command+A Delete, right-click empty printer list for Reset printing system option, download latest macOS driver from support.hp.com, usa.canon.com/support, epson.com/support, or support.brother.com, add network printer by IP address via the IP tab, test from TextEdit or Preview to isolate app-specific issues

Mac: Startup

  • Mac won't start: power cable and port debris check, blinking question mark folder (startup disk missing, fix in Recovery Mode Startup Disk or Disk Utility), Safe Mode (Shift on Intel, hold power button on Apple Silicon), NVRAM reset on Intel (Command+Option+P+R for 20 seconds), Recovery Mode Disk Utility First Aid for file system errors, reinstall macOS from Recovery without data loss, Target Disk Mode to rescue data before repairs

Mac: Files & Security

  • Accidentally deleted a file on Mac: Trash Put Back and app-specific Trash in Photos (Recently Deleted) and iMovie, Command+Z undo in Finder immediately after deletion, iCloud Drive Recently Deleted at icloud.com (30-day retention independent of local Trash), Time Machine hourly and daily snapshots to restore any version, Spotlight and Recents in Finder for misplaced files, version history in Pages and Numbers via File Revert To, PhotoRec free open-source recovery (always save to a different drive), stop using the drive immediately to preserve unwritten sectors
  • Can't log in to Mac: Caps Lock LED check and keyboard layout icon in top-right corner of login screen, password hint question mark after failed attempt, Apple ID password reset from the login screen (appears after three failed attempts), Recovery Mode password reset via resetpassword in Terminal (Command+R on Intel, hold power button on Apple Silicon), FileVault pre-boot screen uses recovery key or Apple ID unlock, disabled account recovery via resetpassword in Recovery Terminal, work and school MDM-managed Macs require IT department for recovery

Linux: System & Network

  • Linux running slow: htop sorted by CPU% (tracker-miner-fs indexing, kworker signalling hardware issues), free -h for RAM and swap usage, swappiness reduction to 10 via sysctl, CPU governor check (powersave caps CPU speed, switch to performance with cpupower), disable unneeded systemd services, drive health with smartctl and Reallocated_Sector_Ct, dmesg for silent kernel errors (ata soft reset failed, EXT4-fs errors, USB reconnect loops), package and thumbnail cache cleanup
  • Linux WiFi not working: rfkill list and rfkill unblock wifi for soft and hard blocks, nmcli device status (unmanaged vs unavailable vs disconnected states), nmcli device wifi connect from command line, lshw -C network for UNCLAIMED driver status, Broadcom bcmwl-kernel-source and ubuntu-drivers install, missing firmware packages with linux-firmware and firmware-misc-nonfree (the most commonly skipped fix for chips that load the driver but cannot initialise the radio), DNS fix via nmcli con modify with 1.1.1.1, restart NetworkManager
  • Linux won't boot: GRUB Advanced options to try previous kernel (broken kernel update is the most common cause), hold Shift or Escape to force GRUB menu on BIOS or UEFI systems, recovery mode root shell with df -h to check for full root partition and apt autoremove, grub-install and update-grub from live USB for grub rescue prompt, remove NVIDIA driver with apt remove --purge nvidia-* in recovery for GPU-related boot failures, fsck -y from live USB for filesystem corruption

Linux: Audio & Graphics

  • Linux no sound or audio not working: pactl info to identify PulseAudio or PipeWire server, alsamixer to unmute Master and PCM channels showing MM, systemctl --user restart pipewire pipewire-pulse wireplumber for PipeWire or pulseaudio -k for PulseAudio, Settings Sound output device check after HDMI or Bluetooth connection, switch to PipeWire with apt install pipewire pipewire-pulse wireplumber, install linux-firmware and firmware-realtek for missing audio chip firmware
  • Linux GPU drivers not working: lspci | grep -i vga to identify GPU generation, Ubuntu and Mint Additional Drivers tab for safe NVIDIA installation, nvidia-smi to confirm driver loaded (table with GPU name and version), akmod-nvidia on Fedora with 5-minute wait before reboot for akmods compilation, dmesg | grep -i nvidia for Secure Boot module signing errors, add nvidia-drm.modeset=1 to GRUB_CMDLINE_LINUX_DEFAULT for Wayland support, AMD GPUs from 2012 use built-in amdgpu kernel module with no extra installation

Linux: Hardware

  • Linux Bluetooth not connecting: sudo systemctl status bluetooth and systemctl enable bluetooth, rfkill list for Soft blocked or Hard blocked state, bluetoothctl for reliable re-pairing (scan on, pair, connect, trust commands), sudo apt install libspa-0.2-bluetooth for headphone A2DP audio on PipeWire, sudo apt install bluetooth bluez to update BlueZ stack, sudo hciconfig hci0 down then up to power-cycle the adapter
  • Linux printer not working: sudo systemctl status cups and sudo apt install cups, http://localhost:631 CUPS web interface for full printer configuration options, sudo apt install hplip hplip-gui and hp-setup for HP printers, support.brother.com .deb package for Brother printers, add network printer by LPD/LPR IP address in CUPS web interface, sudo tail -50 /var/log/cups/error_log for the exact failure reason, IPP Everywhere driverless option for printers from 2019 onward

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