When I installed Norton I had problems with the ATI AiW card and had to re-install many times. Norton always failed after the install, and Symmantec referred me to the website. But hey - I got an answer. I used AVG after that but rubbished the PC when the TV function failed terminally.
I don't have any AV s/w now but then I never open attachments, never allow auto-installations from the net (especially Flash) and generally paranoic permanently.

The only time I thanked Norton was when I got a "returned" mail from postmaster@cresby.com - now just why would I e-mail myself telling me I could not deliver an email I never sent? The attachment was missing - Norton had removed it & I was not aware which e-mail it had dealt with. Since then I open no attachment. save and look at the name. if it has two extensions with loads of spaces - trash immediately. DLL, SCN, PIF, LNK ditto. YEa Yea - exe & com too.