Do not power it up until you replace the thermal paste and secure the hsf.
That goes for all hsf's.
If your still having a problem make it smaller.
Unplug stuff until you get down to psu/mobo/cpu+hsf/speaker....no ram.
If it does not squall for lack of ram your down to 3 parts.
I have an old system that I keep around because of its flexible configuration. It has SATA and IDE connectors, PCI-E and PCI slots, and easily accessible spare bays.
Today I turned it on, for the first time in a long time, perhaps two years. Nothing happened. No invitation to enter BIOS. I swapped monitors; I swapped cables. I used the digital port on the graphics card. No change. After a while, the system turns itself off. I changed the battery; no change. I tried booting from a floppy and from my ultimate boot CD. No change. System has MSI K9N4 SLI-F MB with Athlon 64 X2 2.1GHz. All 4 memory slots are filled, DDR2 PC6400 1 GB each. Four fans work: CPU, case, power supply, and a tiny one on the MB.
I did not find any others. I disconnected everything and still no beeps from POST. What can I check to make some progress on this problem? Or, what could be causing the problem.?
Later, I discovered the CPU heat sink was loose. I'm almost sure I would have noticed it earlier so I'm pretty sure I bumped the lever while unhooking one of the disks. It will take a while for me to get the goo for proper heat transfer from CPU to sink. With the heat sink off, the auto shutoff takes about 30 seconds. Before, it seemed longer and variable, but I had not measured it.