Reboot in Safe Mode and Scan... there could still be viruses it did not detect or could not detect as they were embeded in a program which might not be running in safe mode

i.e. Safe Mode not the once w/ command prompt or networking.
Also get a registry cleaner and clean, clean, clean.
www.cnet.com
Click the Downloads tab... and in the search box type in...
Advanced Windows Care
or
Adware SE or Adware 2008
AVG is fine even if it's the free version as it will tell you where the virus's are to remove manually

as Norton etc just slows you down and gamers hate that.
Also in Firefox get the add-on "No-Script" and it blocks scripts on sites which helps you browse more securely.
S-MAN