Nugent:
Try booting to Safe Mode and logging on as the default administrator, search for the HOSTS file, and rename it something like OLDHOSTS, but don't delete it. (The virus may have made changes to this file to prevent your system from connecting to the most popular anti-virus support Web sites.) Then reboot to Safe Mode with networking and see if you are able to reach one of the Web sites that offer free on-line scanning:
http://www.google.com/search?hl=en&q=free+on-line+virus+scan&btnG=Google+SearchIf that doesn't work, use the Avert Stinger tool that was mentioned while your system is in Safe Mode.
If that doesn't work, see if you are able to access the Registry Editor while logged on as the default administrator in Safe Mode. If you are, let us know. One of us will tell you the location of the most popular keys in the registry where viruses are often located. If you find the name of one of the files the virus uses in one of the registry keys, that will help us determine what virus has infected your system and how to eradicate it.
If you are still unable to access the registry editor, then Bliss' idea seems the best course of action, although you may be able to save some of your data and access the registry once more by doing a repair installation instead:
http://support.microsoft.com/kb/315341The virus may still be infecting your system after such a repair and you will have to take further action to remove it.
Regards,
Doc