Hi there boyboy, I hope that you are personally a lot better than your PC!

You said:

I tried to assemble it myself but it wouldn't turn on!
Did you get any lights, fans spinning, or hard drive noises when you attempted to power up? If you did not, then I would say that I am 99.999% certain that the problem is your power supply (PSU), and your previous symptoms were a result of it gradually failing. Also did you see if the DVD drive would open and shut? The fans would generally not all be powered from the MoBo, and the HDDs and optical drives are fed directly from the PSU.

Because I do this sort of thing regularly, I invested in a fancy PSU testing device a few years ago..........very useful; given that a part of the PSU might fail rather than all of it, particularly if it is dual rail; also the voltages might be wrong.

Could you ask your PC expert if he tested the rig with a known working PSU, and the processor in a known working MoBo; also did he meter/test the PSU?

When you powered up, did you hear any noise or smell burnt plastic? I have known PSUs to turn into MoBo and CPU killers

I am afraid that OEMs frequently use the cheapest components to meet a price point, and the PSU is one of the most common alongside the MoBo.

I think that the "acid test" is the DVD drive door, as that should open and close even if it is the only device attached to the PSU.

I am not knocking your PC expert but it is easy to miss things. I met this old boy in a pub once and after we had been talking for a while, he told me his PC kept crashing after a while, and that he had taken it to a local expert who had replaced the PSU, but it still crashed.

I collected it and immediately saw that the bozo hadn't even bothered to clean the heatsink and fans.....not even the grilles! but I quickly noticed that it had two different memory speeds so I removed the rogue strip and ran it with the original 512MB of Kingston......................worked just fine! so I put the rogue strip into a compatible PC and ran Memtest86..................the screen turned blood red in seconds as it found so many errors, the memory stick was totally hosed.

The computer had been "upgraded" from XP to Vista, and whoever did that had added the extra memory stick. When Vista got busy it tried to use RAM in excess of the original 512MB Kingston RAM, and found the dud stick.

My wife and I delivered it back to him, and he took us out for a couple of drinks, I wouldn't charge him because the IT "expert" had brought the profession into disrepute.................. I also cleaned out all the dust bunnies and replaced the thermal compound.

I look forward to your reply, but still feel that the PSU is the most likely culprit.............you should be able to get another under warranty.

Cheers,

BTW, MLF is correct about the static thing, but given your previous problems with this pre-assembled OEM box, I doubt if that is the case in this particular instance.