Windows 10 and 11: fix it yourself

Work through these in order and stop as soon as the problem is gone. Back up your files first if Windows still starts. Menu names below are for Windows 11; Windows 10 is close but a few settings sit under Update & Security.

The PC is slow

1. Restart (Start, Power, Restart). Shutting the lid does not count.
2. Trim start-up apps. Press Ctrl + Shift + Esc, open Startup apps, and disable anything you do not need the moment Windows starts.
3. Free up space. Settings, System, Storage, Cleanup recommendations. Keep at least 10 to 15% of the drive free.
4. Scan for malware. Windows Security, Virus & threat protection, Scan options, Full scan.
5. Install updates. Settings, Windows Update, then restart.

Still slow with a mechanical hard drive? Replacing it with an SSD is the single biggest speed-up for an older PC.

Windows will not start

1. Unplug everything except power, keyboard and mouse, then try again. A faulty USB device can block start-up.
2. Open the recovery menu: switch on, and as soon as the Windows logo appears hold the power button until the PC turns off. Do this three times and Windows loads Automatic Repair.
3. Choose Troubleshoot, Advanced options, Startup Repair.
4. If that fails, go back to Advanced options and try Uninstall Updates, then System Restore.
5. For Safe Mode: Advanced options, Startup Settings, Restart, then press 4. If Windows works in Safe Mode, a driver or start-up program is the cause.

Crashes, blue screens and odd errors

Right-click Start, choose Terminal (Admin), and run these one after the other:

1. sfc /scannow checks and repairs Windows system files.
2. DISM /Online /Cleanup-Image /RestoreHealth repairs the store that sfc copies from. Then run sfc once more.
3. mdsched schedules a memory test at the next restart.

Note the stop code on a blue screen (for example MEMORY_MANAGEMENT). The same code every time usually means hardware.

No internet

1. Check another device on the same Wi-Fi. If that is offline too, restart the router: unplug it for 30 seconds.
2. Turn Wi-Fi off and on, then forget the network and join it again.
3. In Terminal (Admin) run ipconfig /flushdns.
4. Last resort: Settings, Network & internet, Advanced network settings, Network reset. You will need your Wi-Fi password afterwards.

Starting again without losing files

Settings, System, Recovery, Reset this PC, Keep my files. Windows is reinstalled and your documents stay, but your programs are removed and need installing again. Back up first anyway.

When to stop and call us

• The drive clicks, or Windows reports a disk failure: do not run chkdsk or a reset, as they can destroy recoverable data
• Blue screens return straight after a reset
• The PC turns itself off under load or feels very hot

Tell us what you found. Advice by phone and email is free.