Either BIOS, CPU, or Motherboard problem (i think)

This is a bit of a long story, first of all, this isn't my computer.
The computer several months ago was thrown across a room (anger issues)
The CPU Heatsink Mounting Bracket broke, so the Heatsink would fall off if it was upright. Well now that I got a new heatsink for it, (it worked fine before the replacement, however while it was off the cpu heatsink was picked up and kinda dropped, after plugging it back in, and turning it on, it froze at system boot screen, I shut it off and let it sit for awhile then I tried it again, and it worked fine, I don't know if it would freeze again because i wasn't on it very long) after the new heatsink installation plugged everything back in, I was able to get it to boot, but only by turning on the power, then hitting the reset button. It would boot but after a few minutes of use, it would completely lock up. I know this isn't an OS problem because It would even do it while I was in BIOS. Now there is no POST (no beeps). When I hit the power button, all the devices, as far as i know, have power fine, the last time i was able to get into BIOS the CPU temp was 45 C. I unpluged the cpu power and still everything booted fine except no POST, I have a feeling it might be a burnt CPU, any help would be appreciated
it's a Gigabyte GA-K8VT800M Motherboard and AMD Athlon 64 3200+ CPU

 

If you toss a PC across the room, it would be amazing for it to boot even!
Any of the ones or possibly all (PSU, Mobo, CPU, RAM, Video, etc.) could have been easily damaged there really isn't any easy way to troubleshoot this. Again it might be one component or multiple...

 

I was told that it ran fine for 5 months, I did notice that the Thermal Transfer Compound was all dried up and that the seal had been broken several times, so for awhile, it was just siting on the cpu. Now the computer will only come on for about 3 seconds, still no POST, I did determine it's not a PSU problem, b/c I used another one that i know works, but it still does this. Now i'm probably going to get blamed for it not working, because it worked before it was brought over here!!

 

A PC can run for 100 days without issues and can completely break down on the 101st day, just because you had the system doesn't mean you broke it after all you are not the one who tossed it across the room, right?
Anyhow, again anything could have happened so it is hard to pin-point but you are right it is likely the mobo or the CPU is fried. Here is what I would do (no joke):
Take the whole thing apart including the CPU and heatsink and examine the CPU core to see if there are any discoloured spots or chipped parts to it. Examine the pins, make sure none of them are bent. CPU Heatsink/fan is the first thing that seems to come loose (I shipped a PC to a friend and everything was intact except the CPU Heatsink/fan which was hanging around). The heatsink/fan coming loose would not necessarily damage anything other than the loose part banging around and damaging sensitive components on the mobo so grab a magnifying glass, a flashlight and a Mr. Magoo hat (if you have one...lol) and examine the bare mobo to see if any transistors, capacitators, etc. are damaged.
If all checks out fine on the surface, then grab a compressed air can and thoroughly spray it around the mobo surface, use a straw so you can get into all the slots and CPU bed, etc.
Then apply a thin layer of thermal grease/paste to the CPU if needed and slap that puppy back in its housing. Then re-seat the heatsink, RAM, Video card (if it is an Add-in type) and then connect the power switch cables from the case to the mobo following the mobo manual (or check out the vendor's web site). Do NOT connect anything else, no HD, no mouse, no keyboard, etc.
Remove the mobo battery while you are at it if the mobo doesn't have a reset jumper on it. After 30 seconds re-seat the CMOs battery and then connect the power cord to the PSU, cross your fingers and fire it up...

 

Yeah, lol, I pretty much did all that, except I didn't use a magnifing glass, I took the CPU out before the new heat sink came, to clean off the old dried/crusted thermal paste that was orginally on it. None of the pins are bent, and everything appears fine to me. What I may end up doing is getting a Barebone kit, that just comes with a similar Case (since the orginal is cracked in a few places) Mobo, CPU, PSU, and case fan $100 I believe. Then I can keep the Vid, HD, RAM, heatsink, and other drives. Here is a pic I took after I removed the broken cpu heatsink mounting bracket.

 

Quite possibly the heatsink (heavy metal piece) pounded on the CPU and killed it. It wouldn't really take much of an impact to damage the core of it anyhow.

If someone told me their PC was not working (or working well) after they tossed it across the room due to cookoo issues, I would have told them to toss it again to set things right or break the darn thing completely so they could use it as a door-stop.

"You Can't Fix Stupid" my friend!