Help !! My desktop has a strange behavior

[Tomahawk]

All of a sudden my computer started freezing, rebooting or the screen going black and I here is what I did to try solve the situation, but nothing has worked.
But first the configuration:

Intel D815EEA2 mttherbooard with integrated AGP, LAN, Sound
ATI All in Wonder Pro PCI
384MB ECC Memory
30GB Seagate HDD
Celeron 500 MHz
Creative Labs CD-ROM, NEC CD-Burner
DSL Modem
W2000 Pro

Situation: 5 months running smoothly, suddenlly the problem starts.

Troubleshooting performed:

Replaced Memory
Replaced processor FAN
Removed ATI Card
Scanned Disk, found no problems
Reformatted Hard Drive
Reinstalled operating system

Result:
Same thing, nothing happens, the system hangs, freezes, cannot use start button, hourglass always present.

What is going on?, the only actions remaining are replacing tha processor or the motherboard. Does anyone have any suggestions?

 

[fenix]

Hi Tomahawk, a few possible things that you haven't mentioned. For one, when you say you scanned your disk, I assume you mean that you used the Windows scandisk utility. IF so, also look into scanning the disk for viri with a good anti virus utility. Another probably cause is that the power supply is going bad, or gone bad, and not delivering proper voltages. If you are comfortable with using a meter inside a live box, back probe the power supply outputs for voltages within limits. Especially the power good voltage, which if it goes out of limits, will force a reset of the processor. This would be the easiest thing to try before replacing the mobo. Or just try a new one. P/S's do go bad, especially if you have a low end one under 300 watts with the equipment that you have listed. I think this is the most likely cause of your problem. Processors rarely go bad, so if it isn't the P/S, I'd chg the mobo.

 

[fedto]

I agree with fenix, check the voltage of the power supply, or even replace it. It sounds like it may be dropping voltage or quite possibly the fan may have stopped working, or not moving as it sould and causing it to overheat. I have had 2 go out on different systems. The one will start, but will do funny things at different points depending on the room temperature.
For a quick check, with the system on, look in the back where the power supply fan exhaust is and see if the fan is moving. Alot of times, the bearings go out and it will rock back and forth instead of being smooth.