What happens if your computer refuse to load in windows you can solve that by restoring your computer to earlier time in command prompt also through Sytem Restore take a look how to do it.
- Restart your Computer press F8 button on initial startup.
- When you see Advanced Options Menu ,select Safe Mode with Command Prompt option.
- Select the WindowsXP Operating System .
- Log on With Administrative Privilages and in the Command Prompt type C:\windows\system32\restore\rstrui.exe