Computer doesn't boot

[just_humes]

When the power button is pressed the computer seems to be running fine. The power and activity lights both come on, the fans start and the hard drive and cd roms both start up. After that there is nothing, doesn't even come close to loading the OS. There is no beep and the floppy drive doesn't flash. The computer just seems to stall there for an eternity. The monitor doesn't show anything, just stays blank and receives no signal. Nothing internally was touched. It was working one night and the next morning it was goosed. It has booted very rarely, after countless attempts, but always shuts down randomly.

Is there anything worth trying or should it be launched into the nearest skip?

Cheers

[SnowDog]

If it used to beep and it doesn't now then it isn't POSTing.

Turn it off and unplug EVERYTHING. Leave it for a few minutes then plug the power cord in. Turn it on and see what happens.

If it won't POST it is broken and you need to find out in what way. No POST often means a motherboard fault. Your other symptoms before the total failure could point towards the MOBO and other things.

Is there any USB damage or did this just happen out of the blue?

What machine is it?

[Chaky]

USB damage?

[SnowDog]

USB damage can hold the whole machine down. We have had situations where engineers have been sent out with motherboards and it has been, for just one example (and there are others), the front USBs mangled.

We always check just to make sure.

[Chaky]

I've damaged my PC's in a various numbers of ways (plugging the BIOS chip upside-down, plugging the video card half way in, etc), but never by an USB plug. I guess I'm not THAT clumsy.

[SnowDog]

Had one the other day and the woman's daughter had mangled the front USB by trying to plug a firewire into it (I think it was an iPod).

Pins and front metal surround all bent, and machine having problems.

And don't get me started on when people plug mice, flash pens, or wi-fi adapters in the front, then either stand or lean on the cable.

[Chaky]

If ti gets shorted.... I guess you can fry the mobo.

[doug91]

ok so I just had the exact same problem. Reading this thread I have realized that there is USB damage. Someone was unplugging a USB cable rather violently (yanking it) and then the computer just shut off. How do I repair this USB damage?

[Chaky]

If it doesn't boot any more, all you can do is unplug the USB jack directly from the motherboard. That way you will eliminate shorted USB to be the cause. If it still doesn't boot, then the damage is beyond USB. I say it is either mobo or PSU that is fried. Possibly both.

Repairing the USB jack is simple. Replace it.

[briansmall]

When the power button is pressed the computer seems to be running fine. The power and activity lights both come on, the fans start and the hard drive and cd roms both start up. After that there is nothing, doesn't even come close to loading the OS. There is no beep and the floppy drive doesn't flash. The computer just seems to stall there for an eternity. The monitor doesn't show anything, just stays blank and receives no signal. Nothing internally was touched. It was working one night and the next morning it was goosed. It has booted very rarely, after countless attempts, but always shuts down randomly.

Is there anything worth trying or should it be launched into the nearest skip?

Cheers

What do you mean by nothing?
Does that mean the lights go back off?
And, that the drives and fans stop spinning?

If so, you might have a bad power switch. It happens all the time. To check it, you have to open the box and find where the switch (just the switch) connects to the motherboard. When you find this, you remove the connector from the mbd and momentarily short the contacts. If the system fires up, you have found your problem.

I've seen this several times. Of course it could be something else, but try the simple things first.

Alternatively you can "jab" at the switch randomly and possibly be able to determine that it is the problem.

[doug91]

OK, so I disconnected the front USB ports from my Mobo. I also took out the CMOS battery. Still doesn't boot...
When I power on:
All fans spin
I hear the heard drive
I hear DVD drive
and the mobo light is green.

What else could be the problem?

[Chaky]

If the drives spin, then it means that 5V is still being produced by the PSU. That would rule out PSU. My guess is that the mobo is dead.

In theory, any component can cause the no-boot. RAM, VGA, CPU...

All you can do now is reseat VGA and RAM and hope for the best.

[doug91]

I reseated the VGA card and the RAM, but still the system starts up but will not POST. The fans spin on high power like they do at first start-up indefinitely. Could it really be the mobo. This think is less than 6 months old, and is a high quality ASUS board.
It did turn off right as someone yanked the USB cable out.. but there were no sparks or noise, the system just shut off. Now it won't power on at all.

[doug91]

Also, if it shorted shouldn't there be burn marks somewhere?
I don't see any, but maybe I'm looking in the wrong place..
I

[Chaky]

Use the warranty and do not mention the yanking.