Please Help!!!!

I'm running Windows XP and I think I got a virus, and when I tried to clean it, something happened and now everytime I boot up it says:
Windows could not start because the following file is missing or corrupt:

\Windows\System32\Config\System

You can attempt to repair this file by starting Windows setup using the original Setup cd-rom.

Select 'r' at the first screen to start repair.

When I go to the repair screen, I have no idea what commands to use to fix the file. If someone could please tell me how I could fix it, that would be awesome. Thanks a lot!

 

This link should help it talks about your specific problem
http://www.kellys-korner-xp.com/xp_sys32.htm