Did you crash your system and can only access the safe mode with command prompt? If so, you might want to know how to run the Windows system restore via command line.
1. Step Press F8 on boot up
2. Step Select Run Safe Mode With Command Prompt
3. Step At command prompt type the following command to start the Windows system restore:
C:\Windows\system32\restore\rstrui.exe
(change C: accordingly to the Windows partition)
4. Step You can now follow the instructions and restore your Windows system.
Depending on your problem, a Linux Live CD often comes in handy. For example a KNOPPIX Live CD allows you to start a Linux distribution without even installing the system right from the CD! After booting KNOPPIX you can then access your Windows files and modify any system files.