Computer not switching on. Help needed.

[Kisty]

Hi,
So the the situation is this. I turn on my computer and it has been fine. I was then having trouble with my zboard keyboard to work so I was trying to fix that. Then it stalled, so I switched it off. Then afterwards I couldn't switch it back on!! By 'on' I mean starting HDDs, fans, etc).

I have troubleshooted what might be the cause:

Not power cable - works on the monitor.
Not PSU - works in another computer.
Could be Motherboard - the LED light is on on the MoBo when I switch on the psu
Not GPU or pci cards
Not CPU - Resat it
Not RAM - Resat it
Not Battery used another one from another computer
Could be power switch - though I used both the powerswitch and reset swith in the power switch pins on the MoBo.

My Conclusion:
Could be Motherboard or Power switch

PC Hardware:
Asus K8N MoBo
1GB DDR RAM 400MHz
Athlon 64 3400+ CPU
Radeon X1600pro (AGP)
Win Power 550W (24 pin + 4 ATX 12V pin)

This is the first time in 4 years I've had this problem so it seems very strange.

Any help would be greatly appreciated.

Kisty

[Mak213]

Hello,

My best suggestion would be to try using a different power switch if at all possible to see if it is the switch. Most likely unless you rig something up that would take a different case. That would rule out that issue. But in all honesty it sounds like the mobo is fried.

What color is the light on the motherboard? If it is a solid Orange color that is most commonly a bad sign of a dead mobo.

Cheers,
Mak

[oldskool]

Maybe try another keyboard ? Do you have a spare one laying around? If the POST test can't detect the keyboard on boot-up because of a possible problem with the keyboard, it might be why. Not really sure. The reason I am suspecting the keyboard is because you were having a problem with it to begin with. Or, yes, maybe the mobo I could imagine.

[Kisty]

Hi,
Thanks for the quick response.
I have tried a different switch and...nothing .

Is it really the motherboard that's fried ? Well the standby light is on but I can't get any life out of it let alone POST. It's really annoying me.

What s the minimum amount of things you need to do to switch a computer on, before POST?

Thanks alot,

Kisty

EDIT: The colour of the light is green.

[oldskool]

Check your mobo manual if you have it, there is a jumper you can move to bypass the start-up switch. This way, you can use the power to start it up, and this will let you know if the switch is bad. Newer motherboards (last few years) always have a 5-volt charge to the mobo to keep certain things going. So in actuality, the "switch" on the front of the case is nothing more than an in-between that signals for the CPU to receive a "power good" message, thus causing the CPU to start the boot process and accessing the system BIOS to start the POST process.

[Peter.Cort]

to start it without the switch, just take out the plug in for the power switch, and take a flat head screwdriver and touch the tops of the two pins with the screwdriver, completing the circuit and it should start provided it was the switch that died out.

also you try (one at a time) to take out the cpu/ram/extra cards, (not gfx card) and start it. With the cpu and ram out it should be like OH HEY THERE'S NOTHING HERE BRO WHATS THE DEAL!!??!! that should give you a bit more insight as to what's really going on.

[oldskool]

My bad, thanks for the clarification ! I remember now.

[Kisty]

Ok so now I have:
tried psu from a different comp with ATX 12V 4 pin thing.
tried taking out everything except GFX card
tried jumping the power switch

And they have all failed miserably trying to get the computer on.
I reckon it's the MoBo. .Well I'll be lucky if they sell these sota antiques still...

Thanks alot for all your help. If anyone has anything to add, It'll be greatly appreciated. Thanks again...

And again

Kisty

[CalcProgrammer1]

Take out the motherboard, hold it in the air (still connected to PC, just not touching the case), and try turning it on. It MAY work. The reason is that something metal could be stuck behind the board, shorting out the board and causing the self-test routine to cut power to the board when you try to turn it on. This happened when I rebuilt my old Compaq (the motherboard fried so I upgraded in the same case). There were 2 metal screw pins that were sticking out of the back of the case that shorted out around the PCI slots and the board wouldn't POST, and I spent all night trying to figure out what was wrong, but when I lifted the board up (midnight on a school night) it worked....then I had to go to sleep but the next day I took out the pins and it worked fine, booted up, and installed XP just fine.

[Kisty]

Hmmm I've thought of something that might be the source to the problem. I forgot to add this in.
The keyboard I have is a Zboard. With this keyboard it doesn't like being put in a different USB port. The port I was using was at the front, on the ATX case. The USB port above it was broken, but I could still use the keyboard in the one below. Then the keyboard wasn't working after a day, and when I pulled out the keyboard, half of the USB port came with it. I tried to replug it in and see if it works again. I fear now that I might have shorted out the pc. When I did this, the computer froze so I did a hard turn off, then I couldn't switch it on. I'm going to look at the manual and see if there is anything I can do about this.

Any comments/help would be greatly appreciated.

Thanks

Kisty