Generic Services Host is a Windows module

Generic Services Host is a Windows module, and you'll usually find 3 to 6
instances of it hosting services in Task Manager's Process tab.

Having multiple instances of the generic services host server
running is perfectly normal. I wouldn't be concerned unless one or
more of them was consuming an inordinate amount of CPU cycles.

Description of Svchost.exe in Windows 2000
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q250320

A Description of Svchost.exe in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q314056

What has led you to determine that you do have a virus, now that
we know that you were concerned only with the number of Svchost
processes? This would certainly explain why no antivirus application
has solved your problem - there may well be no virus involved, at all.
What specific symptom(s) and problems(s) are you experiencing?