Hi All

I am having a very frustrating problem that I'm finding it difficult to diagnose, here is the summary....

About 5 months ago when I went to power up my PC, the fans would speed up but not to full speed and the cathode light would flicker on the front, it seemed as though the PC wasn't getting enough power. The way to solve it was to turn off the PSU, then turn it back on and it would boot up fine. This went on for about three months as I never had time to investigate further. Then after getting back from honeymoon in August and powering it on, after a half hour of being in Windows it just powered off. It did this two more times that night. Then I bit the bullet and thought it must be time for a new PSU.

I brought a new PSU and it powered up fine so the first issue was sorted. But it still would power off after some use. I have made done with this as it wasn't as frequent as before. Although it never had a BSOD so it did seem like a power issue still. Then the other night I was gaming and and it powered off twice so I had to give up. After this I didn't know what the problem was anymore - the graphics card felt very hot (although I'm sure how hot it would be normally). So last night I removed the graphics card and used a secondary graphics card that is always installed. I powered up the PC and it fine, or so I thought, it actually ran for a couple of hours until I went to bed. After taking out the graphics card the fan was very clogged up with dust so I thought that could have been the issue. Although after removing the graphics card I received an error during boot: "Warning: H/W Monitor Status Abnormal". Then after going into the BIOS and checking the Voltage, the following readings are in red:

vcore voltage 4.16V
3.3 voltage 4.08V
5 voltage 6.85V
12 voltage 16.32V

After ignoring the message and booting into Windows, it just powers off again within a few minutes. To try and diagnose the problem, I thought perhaps it was the new PSU so I put my old PSU back in but the error still comes up (although the power up issue comes back with this PSU so I do think this PSU has some issue with it). I have removed everything being powered other than mobo, HDD, fans, and CPU. It can't be the CPU as I have tried two different ones now. I have removed my main graphics card (XFX NVIDIA GeForce 8800 384MB) so that can't be the problem. It's weird this error came up after removing my graphics card, so I tried putting it back in but to no avail.

I noticed on other forums that it can't actually be reading the vcore voltage at 4V as it would fry the chips and they suggest it's a monitoring issue.

Does anyone have any thoughts? Is my mobo knackered? I would hate to pay out for a new motherboard if that isn't the problem.

Thanks for reading if you've got this far, I know it's a lengthy post!

Craig