im having a lot of trouble getting Modern Warfare 2 to play right on my iMac. The sound wont play through external speakers, but only through the iMac's speakers and it sounds terrible! Im running win7 64 bit, and I've installed everything from the SL disc...yet still encountering issues. Modern Warfare 2 is running LIKE CRAP! I dont know why, but its sooooo choppy and slow.