I just bought a new AMD phenom ii processor and I was about to place it into my computer when i noticed the heatsink (large silver cube under the fan) was fused to the processor and did not twist off or any other method i tried. Is it impossible to replace processors on prebuilt? can i just pull the processor and heatsink out of the socket without damaging it? (i have the new processor, heatsink and fan)
You'll want to slightly twist the heatsink a bit to loosen it up. Some prebuilts use thermal tape rather than normal thermal compound which does make removal somewhat difficult (although not impossible). As long as the processor remains clamped down, some slight twisting back and forth should not harm anything.