|This is a long shot, but it may help|
If you go to a command prompt (Start -> type in CMD -> right click and "run as administrator" -> type in "sfc /scannow" (without quotes) into the command prompt).
This will scan through all of the core windows files and replace any that have become corrupted/infected. I don't know if it will stop the virus from just replacing them again, but since we don't know what the virus is...it might work!
Hope this helps and please post back with any results!