Every time you remove your heatsink, you must have a clean processor and a clean heatsink, apply a new thin layer of thermal paste, and carefully install the heatsink. If the new heatsink came with thermal paste or a thermal pad already on the heatsink, you will still want the processor to be clean before installing the new heatsink. Basically, you never install a heatsink onto a processor when there is no thermal paste, previously used thermal paste, or improperly applied thermal paste on either the processor or heatsink. Doing otherwise prevents the processor from dissipating heat properly, which can fry your chip.
After you have corrected your processor/heatsink/thermal paste issue, follow the steps listed in the
My PC won't start - Read this first! guide starting with the
Does your newly assembled PC refuse to POST? section. This will take your machine down to the bare necessities and then build it up from there. This will be helpful in finding the problem component.
After you have followed the steps in the guide, update this thread with your results. If the system is still not functioning, please be specific about what worked and what didn't.
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