If Norton is no longer updating, and you don't plan on renewal
I suggest you do the following
Uninstall your version of Norton's
Reboot your computer afterwards
Back in Windows
If you would like to try a free AV
I suggest that you download and install ONE of the below programs
AVG 7 by GrisoftAvast Home Edition by ALWILONLY install one, more that one active AV running in the background can cause system instabilities
After it is installed and updated, run a full system scan
Let it remove whatever it finds