Method 1
You may download & run the Norton Removal Tool to remove Norton completely from your machine & check if the issue persists.
Download and run the Norton Removal Tool to uninstall your Norton product
Method 2
You may also configure the computer in clean boot and check if the issue persists. It will start Windows XP by using a minimal set of drivers and startup programs and helps to eliminate software conflicts.
The following link has steps showing how to perform clean boot:
http://support.microsoft.com/kb/310353