When helping someone debug their computer this comes up a lot. If things aren’t good in Windows-land, getting your computer to boot into safe mode can sometimes give you enough access to your computer to recover Windows. If you need to uninstall a misbehaving application, troubleshoot a blue screen of death (BSOD) or remove a bad driver, safe mode is usually your best bet.
There are two ways to boot into safe mode, and, both of them need you to have a working keyboard that’s recognized by your BIOS (so, if you’re using a tablet PC with a touchscreen, or something like a bluetooth keyboard, you’ll likely need to grab a USB (or PS/2) keyboard to do these actions).
If Windows fails to start completely, you may be presented with a screen like that at left (click the image to enlarge), with the option to boot into one of three safe mode choices or to start Windows normally. If you get this screen, you don’t need to do any other actions to boot into safe mode, just use the arrow keys to select which safe mode you want (usually just safe mode for doing things like software removal and system restores) and press the enter/return key.
If you’re not presented with the choice and want to force the machine into safe mode the easiest way to boot into safe mode is to continually tap the F8 key while your computer is booting (to be technical, after the BIOS screen but before the usual “Windows” loading screen). As long as windows is the only operating system installed, you can safely tap away at F8 from the moment you turn the PC on until the startup options appear. If you have multiple Windows versions installed, when you get to the OS selection screen you’ll need to select the Windows installation you want from the list and then press F8.
You’ll be shown the advanced options menu (see right), and be given more debugging choices including the three safe mode options (Safe Mode, Safe Mode with Networking and Safe Mode with Command Prompt). Choose the one you want and press enter/return to boot into safe mode.