suspected virus

Today I was working on a friends pc (gateway-older model).
It has been running extremely slow, so I cleaned out the temp files, cookies etc. and the system is still very slow

I down loaded Norton Antivirus 2004 and was trying to do a virus scan. When the system tries to scan approx. 10 seconds later a message comes up no virus found. I know the C drive couldn't have been scanned in such a short amount of time.

I am considering reformatting the hard drive. Any suggestions?
Thanks for your help.

Try housecall a free online service.


Then follow the instructions in the first post here.