My mac keeps freezing for several minutes at a time and I've even had to resort to holding down the power button a few times just to reboot the computer. I really only use iTunes, surf the web, and play World of Warcraft on it and I've never had any issues until about a month ago. I'm pretty computer illiterate so I don't really know how to fix or diagnose whatever the problem is, but come this September I'll have had this particular iMac for 2 years. I've downloaded every update I can, iTunes or otherwise and nothing is working. Halp please?