Thanks for the info dudes.
I got the AVG free, but the virus was freezing the computer before it had time to do a full scan, so that didn't work.
I eventually found the file, by right clicking the icon it put on the desktop, and just clicked, 'find file'. I did delete it but it didn't make any difference, as it just kept re-applying itself and re-installing later on....little b'stard!
Eventually just re-booted the system off a disk my dad had. So problem solved...for now.
Unfortunately I didn't have time to back loads of stuff up before it hit. I normally back up at the end of every month, so....
The virus hit when I was on Facebook, on the Fantasy F1 thing. So not sure if thats where I got it from. Used it many times without a problem.