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My first thought is a bad CPU, but it's hardly the only possibility.

Edit: I should have said "a bad or improperly installed CPU..."

Pull out everything but the video card, RAM, and CPU (including disconnecting power cables to devices). Those are the three things a mainboard needs to POST (except power, but that's a given).

Of all the times I've had this issue (fans come up, but no POST), it was usually the power supply. Try scavenging one from somewhere and test it with that if it still won't POST.

If it still won't POST, pull out the video card and RAM. Then boot again. You should get SOME form of beeping as the mainboard finds no RAM or video card.

If it still doesn't beep at all, you're looking at a bad CPU or mainboard. Determining which is the hard part, but the board usually goes before the CPU (in my experience).

There's a speaker attached or connected to the motherboard, right?

Reseat the video card. Try a different power supply.

Has he been messing around in the case? Maybe he managed to fry the motherboard with static electrictiy?

Correct me if I'm wrong, but don't some BIOS's need a bootable device present in order to POST? In any case, there still should be beeps.

Braedley wrote:Correct me if I'm wrong, but don't some BIOS's need a bootable device present in order to POST? In any case, there still should be beeps.

I don't know of any such BIOS, myself.

Destructionator XIII wrote:I might pull the PS out of my computer later to try that, but that is quite a hassle. Is there any other way to reliably test a power supply?

You only need a multimeter. The voltages out should be -5V, +5V, +12V, and 3.3V (all DC). And ground, of course.

As the harddrive is spinning up I'm not all that sure it's the PS. The CPU change idea has merit, I think.
The multimeter approach (assuming one is at hand) makes perfect sense, of course, but I wouldn't yet rule out a bad mobo/CPU.

Nine times out of ten this is a bad mainboard or CPU. The other time it's the PSU.

At work, we usually go for the mainboard first, as that's more likely to have gone than the CPU.

Batman wrote:As the harddrive is spinning up I'm not all that sure it's the PS. The CPU change idea has merit, I think.
The multimeter approach (assuming one is at hand) makes perfect sense, of course, but I wouldn't yet rule out a bad mobo/CPU.

If the 3.3V output is off, it would screw up the CPU. The PS isn't the most likely problem, but it is the easiest to test.

(I realize that it's a bit like looking for your missing keys where the light is good instead of where you might have lost them, but we're stuck with it for now.)

SCRawl wrote:

Batman wrote:As the harddrive is spinning up I'm not all that sure it's the PS. The CPU change idea has merit, I think.
The multimeter approach (assuming one is at hand) makes perfect sense, of course, but I wouldn't yet rule out a bad mobo/CPU.

If the 3.3V output is off, it would screw up the CPU. The PS isn't the most likely problem, but it is the easiest to test.
(I realize that it's a bit like looking for your missing keys where the light is good instead of where you might have lost them, but we're stuck with it for now.)

No argument from me.

Vendetta wrote:Nine times out of ten this is a bad mainboard or CPU. The other time it's the PSU.

At work, we usually go for the mainboard first, as that's more likely to have gone than the CPU.

Agreed - my guess is the system board as well (if you've already followed everyone else's suggestions, that is.)

If you replace the motherboard, make sure you use the same kind or Windows will take an utter shit and won't boot.

The RAM might be loose, which could cause the motherboard to fry, I've done it before.

Natorgator wrote:If you replace the motherboard, make sure you use the same kind or Windows will take an utter shit and won't boot.

Windows is the least of this computer's problems. I'm thinking an OS reinstall is called for.

RAM is the most likely candidate

Either that or

(Holds up staff with the Atari symbol at the top)

The power of Pac-Man compels you! Begon follow cyber-demons!

Destructionator XIII wrote:This is pissing me off. Not only am I having a hard time figuring out exactly what is wrong, it looks like geting replacement parts will be hard.

It is a Compaq machine, and it seems Compaq doesn't use standard power supplies. The wiring configuration is different, meaning if I plug in a standard power supply, it will blow out the board.

The time has come to declare this whole episode a learning experience and move on. I wholeheartedly concur with your inclination to start with new (or at least different) hardware. I don't know what kind of shops there are in your area, but I've seen lots of deals where you can get used and off-lease computers at dirt-cheap prices. P3 and P4 computers can be had for a song, and from the sound of things this sort of machine should be sufficient for your friend's needs.

SCRawl wrote:

Destructionator XIII wrote:This is pissing me off. Not only am I having a hard time figuring out exactly what is wrong, it looks like geting replacement parts will be hard.

It is a Compaq machine, and it seems Compaq doesn't use standard power supplies. The wiring configuration is different, meaning if I plug in a standard power supply, it will blow out the board.

The time has come to declare this whole episode a learning experience and move on. I wholeheartedly concur with your inclination to start with new (or at least different) hardware. I don't know what kind of shops there are in your area, but I've seen lots of deals where you can get used and off-lease computers at dirt-cheap prices. P3 and P4 computers can be had for a song, and from the sound of things this sort of machine should be sufficient for your friend's needs.

And to add to that, you could swap the harddrive out into the new one, and he wouldn't loose any data.

Ok, take a step back for a second. I don't know your level of hardware-fu, so bear with me. Try these steps:

* Remove everything from the motherboard except the cpu, including all the front panel connectos, sensor wires, etc. Make sure you know how to put them back together =)

* Clear the CMOS (it might have got confused).

* You said the power supply has a 24 pin connection. If that's the case, you probably have a 4 pin 12V connector that powers the CPU (in addition to the 24pin main connector). If you do, make sure it's plugged into the mainboard (there should be a 4 pin female connector near the cpu). The machine will not post without this, if it needs it.

* Make sure the cpu is installed correctly, AND the heatsink/fan. The machine will not post without a heatsink/fan (the processor overheats so fast that it shuts down pretty much instantly).

* Install one stick of ram (if you have two). Make sure you only see a hair's width of the connection pins of the ram.

* Install the video card. Again, you should only see a hair's width of the connection pins.

* Connect NOTHING else.

* Connect the power switch, the speaker, and the monitor.

* Try and POST, if it fails, continue on:

* Try the other stick(s) of ram.

* Pull all the ram, and if you have a speaker the mainboard will holler like a bitch saying it has no ram.

* Replace the ram, and pull the video card instead, try a post. The mainboard should beep here too if it's alive.

If none of that works, you probably have a MB/CPU or power supply problem

Destructionator XIII wrote:I am pretty sure it is the mainboard, but the power supply or CPU might be it too, can't be sure with what I have. I will recommend she replace all three with more modern technology; will end up being cheaper anyways.

Agreed. No point upgrading the CPU or the mainboard without the other, and you mightas well get a new PS while you're at it.

Destructionator XIII wrote:I am currently working on a computer for a friend which won't seem to do anything. I turn the power on, and the fans spin up, and I can hear the hard drive start spinning, but that is it.

No beeps, nothing output to the monitor (it just remains in sleep mode). Buttons on keyboard get no result.

This suddenly happened, I've no idea what caused it. I already tried pulling all unneccessary hardware, but same thing.

Any other ideas what I can to to fix this?

Ask her if she ran any disk cleaning software before this happened. I hosed my OS on a Compaq with Windows Cleaner Pro. Of course, it still posted, so...

More than likely the motherboard is fried. You can tell if you open it up and the capacitors are swollen or leaking. Still, you can fish for monitor problems.

Plug in the recovery disk to see if that boots. Highly unlikely if it's not posting to begin with, but anyway if it lights up, find out if the system has since been upgraded; eg: XPSP 1 to SP2 before trying to repair anything. You can't repair SP2 with and SP1 recovery disk.

Plug in a monitor that you know works, and inspect the cable. See if the computer boots on its own, then, plug in the recovery disk that should have come with the computer.

If it's still bust, then check with Compaq's help forums to see if this has ever been an issue elsewhere.

Don't play mix and match with a used power supply out of concern for the motherboard capacitors, but if you have good measuring equipment and know how to test it I suppose you ... well, never mind. If it were mine I'd risk it, but not on someone else.

I suspect you are likely looking at a new motherboard, and the power supply is probably to blame for frying it.

If the computer is not too old, you can probably find a match for the processor fairly easily. If you replace the motherboard, you must also replace the power supply, or you will likely just fry it again.