Get any antivirus that will allow you to boot from a CD ROM and clean your computer first.
I've used several times AVIRA (which is free and allows it), you will need only a blank cdrom and patience...
See:
http://www.avira.com/en/downloads#tools[
^]
You will need the Avira AntiVir Rescue System.
Hope this helps.
PS: keep in mind that a virus is nothing else than a program that is capable to replicate itself into different media without the user knowledge. Knowing that, if you have a virus at any computer, it all depends on which program the virus have in order to know what will happen to that computer...
PS2: There is another thing you should know: there are viruses that can't simply be removed as they are overwriting parts of other programs exe's... if that is the case, then booting from that Antivirus CDROM should allow your to migrate all your data to a hard disk and then reinstall everything without loosing that data...
Good luck!