What version of Norton was the computer originally infested with?  

Did you completely uninstall it using the Uninstall function in the
program or by using Control Panel - Add/Remove Programs.   If not then
you need to do this. And you may also have to get a supplementary
uninstall utility from Symantec/Norton in order to properly finish the
job.  Having two antivirus programs installed can be a real drag on
performance, and can possibly result in the failure to detect some
viruses because of the conflicts between the two antivirus programs.

Good luck

 
Ron Martell     Duncan B.C.    Canada