[RESOLVED] non-booting pc - bios?

[saturdaygig]

I have a pic running windows xp. This morning it wouldn't boot.

It doesn't emit any post beeps, and everything seems to power up - certainly the fan spins, the screen, keyboard and mouse all power up. Just in case, I tried it connected to different peripherals, but with the same result. I say the screen powers up because the power light comes on, but nothing whatsoever appears on it.

I also tried swapping the ram stick for one from a working machine, but no change.

It doesn't seem to get as far as a hard disk access because there's no sound from that. Could it be a bios failure - I can't think of anything else that would cause no start up without any beeps? And if it is a bios failure, is there anything to be done

all advice welcome

[jdc2000]

Check the motherboard for bulging or leaking capacitors. Also, it could be the power supply. Check the voltages and post the make and model.

[SuperSparks]

Try testing the power supply. If you have, or can borrow, a multimeter, here's how to test one:

Testing PSU Voltages

ATX Power Supplies

Trigger Power Supply for testing

In depth look at the power supply

Or alternatively you can buy a proper PSU tester, they don't cost much:

PSU Tester

ATX12V PSU Tester

[dneilson]

You also might want to try resetting the BIOS with the Motherboard jumper or removing the battery for a few minutes and reinstalling.

[Shinma]

Clear CMOS, set BIOS/CMOS menu to fail safe defaults and test for POST.
Disconnect all non-essentials and test for POST.

[saturdaygig]

So, I tried a clear cmos but no change

I decided rather than test the PSU it would be more conclusive to swap it out for one from a working machine. I did that but it didn't make any difference.

I can't see any physical damage to anything on the MB, but I guess we are looking at an MB failure? Or could it be the CPU.

The board is an ASUS P5N-MX running one of the core 2 duo CPUs although I forget what clock speed it is.

[SuperSparks]

Statistically it is far, far more likely to be a mobo failure rather than CPU. CPU failure is rare.

[Shinma]

Ditto.
I would suspect mobo failure before a processor failure.

[saturdaygig]

I'll probably look for one of the same board then, which will save me from doing a windows reinstall. Don't particularly need to upgrade the machine (man, I would never have said that when I had a 386)

[saturdaygig]

So I ordered another motherboard since that seems the most likely culprit. I took the cpu fan off just now and found this - it was only seating down one edge. I replaced this fan about a year ago, so its been like that ever since. On the other hand, the pc has not be shutting down which is what I've found before with overheating CPUs. Any opinions?

[SuperSparks]

An Intel CPU is unlikely to shut down when it overheats, rather it will throttle back instead. You have probably been getting seriously reduced performance at times, but is most likely all that would have happened.

[saturdaygig]

An Intel CPU is unlikely to shut down when it overheats, rather it will throttle back instead. You have probably been getting seriously reduced performance at times, but is most likely all that would have happened.

Ah, right. I nearly always use AMDs, in fact this is the first intel I've used since a P100. We'll see what happens when the MB arrives then, thanks.

[saturdaygig]

So, this is what happened:

Ebay -> troublesome seller who took ages to post -> arrived -> installed -> computer working again

thanks to all

[SuperSparks]

I'm glad you got it sorted out in the end. Thanks for letting us know the outcome