Bad motherboard?

[alangjames]

Some background info:
i have a homebuilt PC, running on windows xp, AMD processor.

my computer worked absolutely fine last night. i loaded it up into my car (i moved today, a 3 hour car ride) last night. I get to my destination and hook up my PC. I plug in the keyboard, it lights up, so it must be getting some power from the power supply. I hit the power on button, nothing, no beeps, absolutely nothing. I check all the power and IDE connections inside the case, in case something got jarred loose during the car ride. There is an LED on the motherboard, which is on, telling me the power unit must be ok. I try again after re-seating all the connections. Nothing. Is the motherboard fried? i left the PC in the car all morning, but it was somewhat insulated by other boxes, with the windows rolled down in <70 degree weather. I cant imagine it got overheated, but i have no idea what could be wrong. any suggestions?

[Heartborne]

Under these circumstances no damage should have been done to your computer. It should be 100% perfectly fine. Try booting without the memory and see if it goes to POST.

[alangjames]

But it wont boot, at all. When i hit the power, the hard drives dont spin, fans dont spin, no beeps, nothing. the power supply fan doesnt even spin, which is leading me to believe it may be a bad power supply? but accessories (keyboard lights come on) still seem to work.

[mjc]

Power supplies provide multiple voltages, so a power supply can be 'mostly dead' and still have some things work.

Bad RAM or even RAM that is worked its way out of the slot can stop a boot process dead in its tracks, even before it starts.

[sassie05]

You said you checked all the connections.
Did you check the front panel header connections? Specifically, the power button connection?

[sassie05]

I plug in the keyboard, it lights up, so it must be getting some power from the power supply.
Oops I missed that on the first read through.
So, when you hit the power button the LED's on the keyboard light up?
Or,
Are you saying at the moment you plug in your keyboard (P/S2 or USB ?) the LED's light up?

[alangjames]

The keyboard is PS2. The leds for caps lock, etc, will flash briefly when i hit the power on button. I tried reseating all the memory with no luck, now the red led that was lit on the motherboard does not light up.

to better explain what happens when i hit the power on switch audibly, it sounds like the computer is not even plugged in, thats the level of "absolutely nothing" thats happening.

[Heartborne]

This one comes up a lot on these forums and if you look through our core hardware forum you'll see many similar posts. There is even a sticky addressing just this type of thing. It gives highly detailed instructions on troubleshooting the issue, so I suggest you start there.
I suggested booting with no RAM; do that and see if it posts. I understood your original question. this is a troubleshooting step everyone here suggests for every no-boot, no video, no nothing issue and most of the time it works.

[Paul Komski]

Common things being common makes the PSU and HDD likely candidates.

However any piece of bad hardware or a bad connection can cause a failure to POST and so you need to go to a basic bare-bones boot. First detach all hardware that can be detached from the motherboard with the exception of the CPU and HeatSink and PSU. This normally produces beeps since there is no RAM. Add one stick of RAM and attach the monitor and keyboard and see if you can enter the BIOS setup.

If not successful try the above with the board removed from the box and sitting on non-conductive cardboard or similar. If no result then either your PSU or Mobo or CPU is almost certainly the culprit.

If you can get into the BIOS setup then add back all pieces of hardware one by one and see if you can discover a culprit.

BTW It's possible all was OK but there was say a loose piece of RAM. Powering on such hardware can occasionally burn-out that component and the mobo and, stating the obvious, Hard Drives don't like any knocks or shocks.

[alangjames]

I disconnected every piece of hardware and ram from the motherboard, tried booting, still nothing.

Shouldnt the fan on the power supply be spinning when its turned on, even if the computer is off? the fan wont run at all, which is leading me to believe it really is the power supply (i hope) im trying to find a replacement to check and see.

[mjc]

Does the current power supply have a voltage selector switch? If so, make sure it is at 115 V (if you are located in North America).

[alangjames]

ive checked the voltage switch, it is set correctly