Got my Mac Pro less than two weeks ago and everything seemed nice and fine. (2.66ghz x1900xt 1 gig ram 160gb hd). After some 20 missions of Call of Duty 2 the game's graphics froze but the sounds kept looping. Had to shut down system with the power switch. After that the game started to do it constantly. After a while warcraft 3 joined the freezers and then even my age-old classic favourite Myth 2 started to faint at odd times(game's about 8 years old but already has an universal binary version (not by bungie though)). Reisntalled OS x and upgraded the firmware and everything. Seemed to be ok until COD2 froze for the first time. After that the other games (that worked ok for hours) started giving up on me. When the freeze occurs the cursor turns to spin wheel for a second and then back to normal. I can move it around (not in COD since it's not visible and in WC3 only in window mode) but I can't do anything. Keyboard goes totally unresponsive. After and during the freeze I usually hear some extra "the computer is doing something" sounds. (not fans, just "crackling"). Recently this has happened during surfing and reading the mail. I did some memtest found on macupdate and ran the Apple's hardware checker. Both came out clean. Now it's gotten to a point where COD2 crashes during first five minutes and Myth during perhaps ten or so. Rendering both unplayable. And me very pissy. Tried changing HD to another bay but when I pluged it to bay number two the sound it made was just gut wrenching. The whole computer resonated with it. Now in bay three it's back to same old crash and burn. any clues?