How to start System Restore when you can't boot into XP

If you're having problems that prevent you from booting into the GUI, you may still be able to use the System Restore tool to roll back to a previous operating system state, and thereby fix the problem. Here's how:
1. Restart the computer and press and hold F8 during startup to bring up the options menu
2. Select "Safe mode with a command prompt"
3. If you have multiple operating systems installed, select the correct instance of XP
4. Log on with an administrative account
5. At the command prompt, type
%systemroot%\system32\restore\rstrui.exe
and press ENTER
6. Follow the on-screen instructions