I found this subject discussed on the web. See link below. One of the posters on the forum suggests this. I use Norton but have not had the problem. Hope this helps.

Open Norton Protection Center
Click on Norton AntiVirus tab at top
Expand "Settings" and scroll down to bottom for Additional Options -> Virus and Spyware Protection Options
On the left-hand side of the screen that pops up, click on General Settings under Manual Scanning
Uncheck the second item, which should be "Scan active programs and start-up files"
Again, on the left-hand side, click on General Settings under LiveUpdate
Uncheck the second box there, too. It should be "Run quick scan whenever protection updates have been received"

• http://www.cybertechhelp.com/forums/showthread.php?p=730140