Dead motherboard, am I right?

[AnitaPeterson]

Hi folks,

I have a problem which defies all my attempts to solve it.

Here's the scenario:

I found a discarded Acer desktop, missing its RAM and HDD.
It's a Socket 775 Q6600 CPU, on a no-name motherboard (probably built for Acer by some OEM manufacturer). I checked the processor, cleaned it and the base of the cooler, added fresh thermal grease and reseated the cooler.

I figured it a q6600 system may still be useful if rebuilt. Four slots of DDR2 RAM on the motherboard also give it some breathing room.

Now, the first problem: the computer won't start with four identical 1 GB RAM sticks. Any random two of them will work, if they're in matching slots. Otherwise, the screen stays black. No beeps, either.

I found this strange, but I figured I'll just boot it with 2 GB RAM and troubleshoot later.
Wiped out the BIOS (replaced battery).
Added a SATA HDD.
Installed Windows 7.

The monitor is connected to the onboard video.
All other peripherals are a keyboard and mouse.
All seemed to be working.

And then I turned it off.

Upon restart, I got a screen directing me to either "repair windows" or "start normally".
Choosing either one of these options results in the machine shutting almost immediately. Not a restart, just power off, as if the PSU switch is thrown.

I tried the following:

1) Different (and known to be good) power supply - shutdown.
2) Different HDD, another fresh Windows install - shutdown just after Windows is installed, and loads for the first couple of times.
3) Different SATA cable - shutdown.
4) Moved the RAM sticks to the other color-matched slots - shutdown.
5) Different power switch attached to the motherboard pinouts - shutdown.


The only thing that seems to be clear is that the system will power on, go to BIOS and stay on for a seemingly indefinite time. It only turns off when an operating system is launched (regardless of the HDD in use or SATA port the disk is connected to).

I looked at thermal data, even disabled the temperature limit shutdown, but the CPU shows normal temperatures anyway (30 C, with 22 C ambient).

I can't come up with any other testing scenarios.
At this point, I can only think that either the CPU is on the fritz, or the motherboard is flaky.

Since CPUs are rarely going bad, the most likely explanation I can think of is that the board is unstable.

I don't see any bulging caps, but that doesn't mean something else couldn't have gone wrong.

Am I correct in thinking the mobo is toast?

 

[Shmee]

Very likely the motherboard is the issue, though it could still be a CPU issue. If you can boot into a bootable linux with a stess test available for CPU. I would also try running memtest86.

 

[AnitaPeterson]

I attempted to load a Linux Live CD and it shut down again.
I'm going to just call it quits... At this point it's more trouble than it's worth...

 

[DAPUNISHER]

Do you have a PCI or PCI-e vid card? That would be the last thing to try if you have an old card that is compatible. I know some did not have PCI-e slots, so a a PCI card can be great for troubleshooting old stuff. Not that a system that old is worth much time or effort, as you pointed out.

 

[AnitaPeterson]

Ah, yes. I tried both the onboard video and an added PCIe video card.
Still getting shutdowns.