Do you recall the name of the virus file?
Have you tried >tapping< the F8 key when the computer is making an attempt to start, and get to the Advanced Options Menu, where you can select >Safe Mode with Networking<?
Is the computer a 32-bit, or 64-bit system?
Post back with the info above.^^
If nothing works, you may need to use the Microsoft Standalone System Sweeper program:
You need to use a clean cpmputer to download and burn the program to CD, or follow the instructions for using a USB flash drive.
Retired - Doin' Dis, Dat, and slapping malware.