Purchased: Aug '07 Model No: A1186 EMC No: 2138 Mac Pro/3.0_8CX/4x1/2x7300GT/500/2xSD/AP/BT Logic board: Part number: 630-7951 Serial Number: J5*****X7QB Upgrades: Added: 8gb Kingston memory (total 12gb) Added: 3x1tb drives (total 3.5tb) Couple weeks back, system blinked off. The machines powers on, but there's no chime and the system doesn't boot at all. Done the SMC reset, reseated RAM, drives, video cards etc. Suspected the logic board. Troubleshooting (from Frys, Apple authorized) confirms it's the logic board. Now, going through the process of pulling the old board to trade in for a replacement "X7Q" board. Probably this one: http://www.galaxyhp.com/Mac-Pro-Early-2007-8-core-Logic-Board-ver2-new-wexchange_p_177.html I got the machine disassembled but I am unable to remove the heat sinks/CPUs. The 4 captive screws loosen, even took them all the way out of the machine, but the sinks seem to be stuck. It doesn't just lift out as most of the online info I've found indicates that it should. Unsure of how hard to pull on this thing. It wobbles very slightly, but feels firmly stuck on...enough that the board will flex if I pull it any harder. More reading makes me think it might be the thermal paste is just really sticking? This is really stuck though...almost as though there's another screw I can't see. I thought if I pulled hard enough the CPU might come out along with the sink. Also I ran across an article (after the fact) that states the order of screw removal from the heat sinks needs to be in a specific crossing pattern. Can't imagine how that matters. Of course, I paid through the nose for this machine back in late '07. Bought Apple Care even. All long since expired...now that I need it. Getting desperate. This machine is a workhorse and I see no value in replacing it if I can fix it for 700 to 800 bucks. Any one have ideas?