Thought I would give this thread a bump for those who haven't seen it yet.
2. When installing heatsinks that require a flathead screwdriver to remove the clip, remove the
PSU or at least uninstall it and set it to the side. Many motherboards have died a horrible death from flathead screwdrivers. If the
PSU is in the way, you may not be able to get enough leverage on the clip to remove it. Also, use the correct size flathead for the clip, generally a Craftsman 3/16" works best. If you use the incorrect size screwdriver, like a smaller XCelite or one that is too large, the head may slip and mess up some resistors or even the
PC board itself. My ECS K7S5A died because of the wrong size screwdriver.