SR-71 Blackbird said:
If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you will need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.
If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to start, and then press F8.
On the Advanced Boot Options screen, use the arrow keys to highlight Last Known Good Configuration, and then press ENTER.
Good idea here, that will use a copy of the registry from the last time the PC booted normally, which is what you are looking for.