Is your Windows computer not starting up normally? Is it crashing on startup? May be you installed some new hardware or program recently which is causing your Windows OS to become unstable and crash. Luckily there a way you can try to login and fix the fault causing component. Windows has a feature called as Safe Mode. In this mode  the Windows starts the Operating System with a minimal set of drivers and processes. By doing so you can login into windows like before,  troubleshoot and fix any issues related to hardware or drivers or your installed programs that may be causing your Windows to not start normally.
  1. In order to enter Windows 7 Safe Mode, turn on or restart your PC.
  2. Now just before the Windows 7 splash screen  appears, press the F8 key to enter Advanced Boot Options.
  3. Once you enter the Advanced Boot Options, choose the Safe Mode option  and Windows will start in Safe Mode this time.
  4. Now login into your computer using an  user with Admin privileges.
When your computer is in safe mode, you'll see the words Safe Mode in the corners of the display. To exit safe mode, restart your computer and let Windows start normally.