I apologize in advance, because this is long.

I made some small upgrades to my old VAIO computer last summer, switching out the mobo, processor, and case; but soon I found the stock Intel fan was making WAY too much noise all the time. So I looked up and bought a new fan. I bought the Zalman CNPS 9700 LED CPU cooler, feeling really cool about it, not expecting any problems with the size.

As it turned out, it fit in the case, but in order to screw it in I had to remove the power supply. The heatsink/fan came with its own mounting apparatus, which I screwed in tightly, I used Zalman's included thermal paste on both surfaces before putting the fan down, and I held it down with its clip. Now the fan is able to shift a little even with the clip installed, and that made me a little nervous, but not very. I stored the case upright, so that the mobo was vertical and the fan stuck out horizontally, held against gravity by the mounting clip.

One day, the computer just didn't start. No beeps, but the mobo just shut itself down a few seconds after starting. I opened up the case, removed the fan, reapplied thermal paste, replaced the fan, and started the computer again. Everything worked as normal, and thereafter I left the case horizontal so that the fan would stand upright and not move. So it was for two months.

Two weeks ago, I straightened the case again to vertical position so that I could take it with me when I moved. I started the computer after making it go upright, and a slow series of long beeps came from the speakers, and nothing else.

I tried removing everything, reinstalling the mounting apparatus, regreasing (with a new grease since I lost Zalman's thermal paste) and putting on the fan, reseating the RAM, and even the bad idea of shifting the fan around on top of the processor, but no dice. The fan starts, the motherboard lights, and it does nothing else except a slow series of long beeps.

Is it dead for good? I don't have any other Intel processors or motherboards, so I can't test the components separately, unless I give up and give it to a repair shop. What can I do?
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Intel Pentium® 4 541 Processor Prescott 3.20GHz, 800MHz FSB, Socket 775, 1MB Cache

Asus Intel P5VD1-X LGA775/PT880 Ultra/PCI-E+AGP Motherboard

Zalman CNPS9700 LED CPU Cooler

Did you thoroughly clean off the old thermal paste before applying the new thermal paste ?
How much thermal paste did you put on ? You only want to put a thin layer, especially if you're putting it on both surfaces.
Did you check the CPU temperatures before you started having problems ?

Actually, you're not supposed to put paste on both surfaces, just the CPU core. And you should only be using a dab approx the size of a BB or grain of rice. If it's a dual core CPU, this "dab" should be placed in a thin line so that it spans across both cores. Follow the Arctic Silver instructions:

http://www.arcticsilver.com/ins_rou...

Jam: The directions in your link for arctic silver might be the best way to apply thermal grease, but Zalman gives the following directions for their product: http://www.tweaknews.net/reviews/za...
Notice that the picture also shows the grease applied to the whole surface of the cpu-I'm not sure that was a dual core, though. Also, it is not clear if this is what the OP was using.

Thanks everyone for replying. I did check the CPU temperatures, they were pretty low with the Zalman when it was working.

I did lighten the layer of thermal paste and try starting again, but the computer's response was the same.

Maybe the first time I started the computer after straightening it was when it fried. It did take me a little longer to turn it off that time.

I think I'll take it to a shop to troubleshoot the mobo and processor, but if I don't find one locally I'll just buy another cpu.

Thanks for the input.

What about the stock Intel HSF -- what happens with that installed?