Personally, from someone who has worked on and repaired computers for many a year, I always suggest to people that they get rid of Norton because this program causes more problems on computers I have fixed than any one single program. The reason being is that Norton puts a gazillion files on your computer, hidden ones as well. One cannot just delete Norton in the normal way either. All of the files are not taken off. One has to go into search and find anything related to Norton to get rid of it all.
So, with that many files, it is no wonder to me that people have problems with it. You say that it doesn't cause problems with other programs on your computer. Well, if you are using what came with the computer, that has already been fixed by the Computer company. However, if you add a lot of programs to the computer, then you will see problems with some of these programs working with Norton. At least, I have seen many that won't work with Norton.
I am not saying that is your problem, however it does appear to me like a problem with the way your computer is set up or a clash with another program.
I would try running the game with all of the programs you see on the right side of your task bar turned off and see if this makes a difference. If not, then I would go to the manufacturer of your computer and make sure you have all of the latest updates. Also make sure that you have all of the latest Microsoft updates on your computer as well. Do a defragment of your computer. Run an adware and malware check program to see if one might have snuck in through some back door. And finally, if none of these suggestions help then go to the nearest window to your computer, open it up and then throw the damn computer out it.
Just kidding with the last thing. If you are running Vista, this could cause more problems that are almost impossible to find. That is why I gave up on Vista a month ago and am running XP Professional now. Works great and faster.
Anyway, just some suggestions. If you are running a Mac, then I am afraid I have no advice. I have never run a Mac, and never would. Just me, so no comments from the peanut gallery please.
Good luck with it anyway!