GA-MA770T-UD3 will not boot past POST screen, CPU fan stops

[Galli]

Hi,
my PC will not start up. It stops at the post screen, I can't enter the set-up and it won't boot from a CD.

Last evening, I shut it down and it started to install 1 of 6 windows updates. When I came back in the morning it had locked up with the screen still displaying the same message of "installiing 1 of 6 updates".

I switched the PC off with the soft off button but when I switched it back on, it only got as far as the post screen and just hung there. The hard disk LED comes on and goes off, hard disks are spinning up OK.
I have the cover off and noticed that the CPU fan starts, runs for a few seconds and then stops.
If I leave it on, the CPU still heats up - so I have not left it running for more than a minute or so.

So far I have tried unplugging the hard drives, resetting the CMOS, moving the RAM to a different slot.
The main board, CPU and RAM were a recent upgrade and have been working fine for a couple of months.

Any suggestions on what else I can try to get it up and running or what might have gone wrong ?

Components are :-
GA-MA770T-UD3 motherboard version 1 with the latest BIOS (as far as I can remember)
AMD Processor
1 x 2gb Crucial PC3 ram
Geforce 7300 graphics card

Running Windows XP SP3

Thanks,

Galli.

[Dark Mantis]

Hi
I would recommend clearing the CMOS again. It sounds like maybe it didn't work the first time. Remove the power cable, remove the battery from the motherboard and press the power button to dissipate any remainiing power in the PSU. now short out the battery terminals on the battery case with a small screwdriver and leave for ten minutes. That should make sure that the CMOS is clear.

[Galli]

Hi,
I have now tried that, with the boot disc plugged back in. The CPU fan now remains on but the PC still hangs at the POST screen - it won't let me into the BIOS. The hard disk light comes on for 20 seconds or so, then goes off and the PC just sits there humming away.

Any other thoughts ?

Galli.

[Dark Mantis]

Have you got a buzzer attached and if so what beeps does it make?

[Galli]

Hi,
it currently makes one beep when starting up. I think that is what it usually does but I've not paid that much attention in the past.
One time (while trying to figure this out)  it made 4 beeps in a row with a small gap - an so on till I switched it off, but it has not done that again.

Galli.

[Dark Mantis]

One beep means that the POST sequence has completed successfully. One long and three short(four beeps) would mean a keyboard error so maybe it would be worth checking that out by swapping it out for another keyboard .

Another thing to check is that the cooler is tightly fixed down and working properly.

[Galli]

I checked that, no difference.
Perhaps it is not stopping at the POST but at the next thing in the sequence - not sure what that is though since the Gigabyte screen comes up and I can't see what is happening.

[Dark Mantis]

In that case you have to enter the BIOS and change the option to show splash screen so that you can see what is happening if you can get that far. Try pressing DEL when it is POSTing and see if it will take you to the BIOS

[Galli]

That is one of the problems - I can't get into the BIOS at all.
I have tried a known working keyboard as I still have bits of my old one but that didn't work.

I just swapped out the PSU to see what effect that had. The old PSU I have does not have an ATX 2x2 connector that the new one has. It is also 250W. Anyway, the PC would not work with that one even with verything but the hard disk un-plugged. I expect it is a bit under powered.

[Dark Mantis]

No I agree 250w even if it is still running at full power isn't enough to boot the system and it definitely wont work without the extra 12v connections. The only thing you could do is to use it as a slave and run them both just to check the power output is enough. What PSU are you using anyway?

[Galli]

The one I have is 600w and has been working OK.
Just checked the voltages with a multimeter, I'm getting 11.99, 5.12 and 3.36 so that looks OK I guess.

[Dark Mantis]

Were those voltages measured under load?

[Galli]

Well, I measured them with the system in the hanging state so not under a specific load. The boot disk was spinning and the CD draw opens and closes so they are getting power.

[Dark Mantis]

Probably OK just a little concerned by the 12v line. I would say it's fine if it was taken under load but at quiescent state it might be a little low.

[Galli]

Hi,
not sure what else to try now other than sending the MB and CPU back to Gigabyte and AMD.

So, all that is attached to the PC and the moment is the boot disc, DVD, graphics card, keyboard (the Numlock LED goes on and off when the key is pressed but the Capslock LED does not)  and mouse (the mouse light underneath is not lit), one 2GB RAM stick.

When I press the reset button, I get a quick flash of a screen that says ..

PNY Geforce 7300GS PCI-E
Version 5.72.22 46R6H3
Copyright (C) 1996-2006 Nvidia corp
256 MB RAM

... then into the flash screen and hangs.

(just going out for a few hours right now so will have to coninue trouble shooting later - thanks for your help so far !)