if you get that error, and it mentions that "savscan.exe" had some error and gives you a long number reference thing - i can't remember what it was, but it looks like this(or might even be this):
Internal Error 2753:
you've dug norton out of the registry, reinstalled it 64times and can't find anything on the net(especially not on symantec's website, because they want you to send in a 7MB log file so that they can see what's going on)...
when all else fails, try creating another user account and give it full administrator rights. try installing norton using that user. after installing it and activating and what-not, you can delete the user account. i stumbled onto that cure and now my co-worker is claiming credit for installing norton(after i did the hard work... i'll get back at him by making him cold coffee!!! mwahahahaha!!!!).
i'm hoping that will work for you. if not, then sorry... i heard "bitdefender" is pretty good. :)