google for hirens boot cd - there are utilities on there that can help and as it works "outside" of the infected windows environment, it can be successful when other approaches are not.

HTH

One suggestion for the non-expert IT person, is to install and run the Avast Free AV program. Not so complicated as Hi-jack etc.

The good part, is it give an option to run a boot check in DOS mode - i.e. before Win loads.
Ensure you update the Vir def files before proceeding. After completion Avast is easily uninstalled.

I have used this a few times and it has found and removed all malware, fake virii detectors etc which various relatives/friends have allowed on to their machines.

+1 for avast I've never had a problem with it and if a virus is trying to get in it will 9 times out of 10 it will automatically cut the connection to the download!