WoW blocked from updating

I’ve used this antivirus for quite a while, and this problem has never popped up before. World of Warcraft can’t update properly and the program itself is freezing randomly. All of my other programs are up-to-date, so the only thing I can think of is my copy of the antivirus blocking the program from completing any patches or repairs. I’ve let the battle.net programs through Avast, and even run the battle.net launcher as administrator, but the problem persists. If this keeps up, I’m going to have to uninstall your antivirus to fix the program I got this new computer to run. I’ve been satisfied with your product before, but now my satisfaction is dropping. If I can’t use the program I got the computer for, then finding a new antivirus my be my only option.

If this keeps up, I'm going to have to uninstall your antivirus to fix the program [b]I got this new computer to run.[/b]
Did this new computer come with a preinstalled antivirus from factory? If so, did you remove it according to that vendors removal instructions before installing avast?