PC won't turn on ??..

  BaboonBoy22 10:35 09 Jun 05

After I shutdown my pc, the lights on the optical drives remained on and I could hear a fan still going.. presumably the cpu. I tried turning it back on and shutting it down again, but it did the same thing. So in the end I just unplugged it. The next day I went to turn it on.. but it wouldn’t, nothing.. no lights.. no anything. So I thought it must be the psu.. tried a different lead first, that didn’t work. Brought a new psu, installed it.. and that didn’t do anything. Checked the power switch.. and that’s working fine. So I have no idea what it could be. Please please could anyone help me out??

  mattyc_92 10:52 09 Jun 05

Sounds like a problem with the motherboard.... Have you got a spare motherboard lying around the house? If so, then replace the current one with that one and see if the system to boot...

The motherboard is the thing that re-acts to the power button, so maybe the BISO is damaged?? Try resetting the BIOS (consult your manual as there may be a jumper setting you can change to do this, otherwise, just remove the CMOS battery which is that silver disk and leave the system for around 10 minutes before replacing it)

  BaboonBoy22 14:03 09 Jun 05

Yea I was looking at that yesterday.. it does have a bios jumper. The manual for my machine.. is.. well..crap. What do i do just take it out and put it back in?? Sorry my knowledge really doesn't go this far into things. Also do i need to worry about static issues when doing this?

  mattyc_92 14:23 09 Jun 05

Static... YES.... "Ground" yourself every so often especially if you move around the room/stand-up (just touch the chasis for a while to "discharge" the static in your body)

Method 1:

If this was your jumper settings at the momemnt:


| - Covered

| - Covered

Just take that pin cover thing and replace as follows:

| - Covered

| - Covered


Leave it like this for a few seconds, and then replace it back to how it was origninally

Method 2:

You could just remove the CMOS batterey by lifting up the leaver that holds it and slide the battery out... BE CAREFUL as it is quite easy to break the leaver off the motherboard... Leave for around 10 minutes and then replace the battery

Only use ONE of these methods, as both will result in the same out-come.... Your BIOS will be reset to "default" settings

  phono 15:07 09 Jun 05

As a word of caution, I have seen some mobo manufacturers recommend that the mains lead is disconnected before resetting the BIOS via the jumper method.

This is presumably because an ATX PSU is always supplying a voltage to the mobo, even when the computer is switched off.

Also make sure that you put the reset jumper back in the original position or again you may cause damage if you switch on.

If for example you have pins 1, 2 and 3 and currently the jumper is across pins 1 and 2 you would move the jumper to pins 2 and 3 for a few seconds before replacing across pins 1 and 2.

  BaboonBoy22 15:20 09 Jun 05

Is there an explanation as to why this happened, or is it just one of those things. By reseting the BIOS.. what is actually happening? (Sorry don't mean to be a pest, just interested in the why's and how's.)

  phono 15:34 09 Jun 05

Is your computer working okay now after trying a BIOS reset?

I personally have never had such a problem as this. I would assume that for some strange reason the BIOS settings became corrupted thus preventing the computer switching on. By doing a reset the settings are set to default failsafe settings.

The reason it happened in the first place may be down to a failing CMOS battery, failing PSU or possibly even fluctuations in the mains voltage.

Some BIOS chips are socketed and over a period of time they 'creep' out of the socket, this is probably caused by the expansion and contraction of the pins of the chip and the socket as the computer heats up when on and cools down when switched off.

The common cure is to ensure the chips is seated firmly in the socket by pressing it into the socket, but be careful as too much pressure will crack the motherboard.

  Fruit Bat /\0/\ 15:35 09 Jun 05

Power settings can cause BIOS settings to become lost.

Have you reset the BIOS?

Does the PC boot now?

  BaboonBoy22 15:50 09 Jun 05

I haven't tried it yet, as the problem is with my home pc and I'm at work. But as soon as I clock off i will try. Will keep you all posted. Many thanks for the help so far.

  griffon 56 16:09 09 Jun 05

Here's a tip I was given for continuously discharging static on the computer case and of course from the body. Put a double-pole in-line on/off switch in the mains power lead and carry the earth lead unbroken right through it to the computer power supply. This means that the computer is always earthed through the mains neutral earth return and touching the case will discharge any static on your body. It will also allow you to isolate the computer from the mains voltage without unplugging.

Sorry it doesn't solve your problem BaboonBoy22, but that looks as though it is probably a mobo fault since from what you have said your machine doesn't even get as far as booting up, it fails at the Power On Self Test stage. Have you checked that the power supply plug is properly seated on the mobo. They're often near the IDE connectors and if you've ever had to move these in fitting a new hard or optical drive it might have become disturbed. The power connection is also done by a hold-on relay which might not be making, and if you've had cause to take off the front panel and it's not reseated properly there's a possibility that the prod of the on/off switch isn't reaching the switch itself. You could try checking the power supply outputs with a meter to see if any are not showing a voltage or showing one when they are not supposed to. At this stage I wouldn't think it was the BIOS though resetting it wouldn't hurt. Good luck.

  BaboonBoy22 16:27 09 Jun 05

Another quick question.. when I reset the BIOS, do I run any risk of loosing any data? I'm probably just being paranoid, but rather safe than sorry and all that.

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