if somehow you did get a virus on the restore it wouldn't change in to a different virus each time.

put norton back on make sure the first thing you do is get all the updates from norton and keep real time protection on. you couldnt have been doing this or you wouldnt keep getting infected. and have you been making restore disks as you go? if you dont make restore disks every time up add somting norton cant restore it. if you keep your av updated there shouldn't be any need for restoring. ive never had to use norton restore.