what did you scan and remove the virus with? if it was a onboard scanner it may not have removed all the viruses. try a online scan to see if you got it all.
http://www.pandasoftware.com/actives..._principal.htm
have you scanned for spyware?
http://download.com.com/3000-2094-10...ml?legacy=cnet
if both turn up nothing or remove something and the problem persist, do a repair of the operating system with the install disk.