HP 8200 CMT boot problem

[Recycler66]

I'm working on trying to start a home storage NAS with this HP 8200 cmt and i can get the computer to boot. I removed everything and started from scratch installing things and i get 2 beeps and cpu and case fan starts then shuts down a couple times then nothing. I thought it may be over heating as 2 beeps says that it's power thermal shutdown so i removed heat sink and noticed the cpu was covered with thermal compound but not much was on the heat sink. i cleaned both items and re-applied MX-4 thermal compound on processor and tightened heat sink down and i got the same 2 beeps again. I replaced with an identical power supply from another 8200cmt and still get 2 beeps. It did run fine about a month ago and shut it down but now it won't boot now. i'm thinking the motherboard is possibly shorting out or motherboard is gone?  Any help would be much appreciated

[itsmyname]

@Recycler66 -- is the motherboard on that "other" computer still OK? If so, try putting your CPU into that motherboard.

Does your computer have integrated graphics, or an add-in graphics adapter?

If there is no add-in graphics adapter, add one, to deactivate the integrated graphics.

If there is an add-in graphics adapter, remove it, and re-insert it, to make sure that it is properly seated.

Or, if there is an add-in graphics adapter, remove it, and install a different one.

Try booting with only one stick of RAM, in case one stick is "bad".

[Recycler66]

i t seems the "other computer is not identical..it's a 8000 model...processors are different. What i have here is a 3 bay Istar hot swappable cage and it should fit in the other computer if this one is a no go. I go the computer for nothing and it has an I-5 in it..shame to just throw it in the trash. i love recycling computer and either giving them away or selling for my cost. I have boht integrated video and and Gt520 video card but can test neither atm..I tried booting with different sticks of ram and each time i seem to get a different boot. Sometimes the computer boots and cpu cooler and case fan spin and then stops. It spins up again and then stops and sits idle. I thinking it's possibly the motherboard or the power supply is weak but it works in the other computer fine