I went round and round with Activision about this problem... I was taken from the general support through email and sent to actual techs. It took about 2 weeks before they realized they didn't know what they were talking about. With some computers the simple fixes you can find from googling will work. My problem was different. This is the latest email I received from Activision:
It appears that you are using an Nvidia Nforce based motherboard and the issue may be that the Nvidia firewall (called active armor) and Nforce Intelligent Application Manager that was installed is having trouble with the game.
-Uninstall any existing nForce networking drivers prior to installing this package.
Maybe give it a try if your mobo fits the profile... It worked for me. From what it seems, the game does NOT like programs running in the background. I agree, they need a patch. Fast. Dedicated servers would be nice to come with that patch