Should not be.
To my best knowledge viruses do not overclock CPUs.
They may damage (BIOS), however (Chernobyl virus).
If you feel, that your computer is infected please
post to microsoft.public.security.virus and describe your problem in more
details (i.e. whether you see anything on the screen when you try to start
your computer, and if you do, what do you see)
Regards,
Yuriy