Help I am baffled

[shifty]

PC will not switch on with mouse and keyboard plugged in at all. Unplug both and it powers up no prob.

Ive reset the bios and that solved everthing for a short while but it seems after a successful boot up and shut down with the mouse and keyboard it then just returns to this state of not switching on.

I tested the cmos battery and its putting out 2.6 volts

[phishphreek]

Is this with ps2 devices? Do you have this problem with USB devices?

[thierry101]

Likely USB.

[nihil]

shifty, I would say "welcome to AO" but perhaps I should say "congratulations on your first post in five years"

Please tell us:

1. What operating system and update level (service pack) you are at.
2. What make and model of computer you are using.
3. If it is not a proprietary brand, we would need to know the motherboard make and model.
4. What make and version of BIOS are you running.

Your CMOS battery is running low, but should not produce these results.....it should be about 3 to 3.2volts

Now, I have a question for you:

Why did you bother to mention the CMOS battery voltage, when you did not provide the more relevant information that I have just asked for?

EDIT: What other things have you tried...... like if you know the battery voltage, you must have gone pretty deep? hell's teeth, I haven't the faintest idea of the CMOS battery voltage on this box

[shifty]

well this is my guess. i know that a low cmos battery can cause all kinds of problems with forgetting settings etc which can sometimes upset the boot process. However, not switching on at all is a little unusual.

Next...is there something shorting on the mboard...nothing obvious...how the hell can you find it if it has been scratched in any way...by perhaps a slipped screwdriver in the hands of a lunatic.

finally i notice that the metal surround is missing from the 2 onboard usb ports at the rear. If this has been removed/lost then i think there is a possibility that it may be causing a short or even not making a contact that it should be and perhaps a circuit is either incomplete or damaged through a voltage change.

[nihil]

Correct,

If the CMOS reverts to the basic, default settings, the thing should still boot properly. Yes, you should replace the battery, but that is not your current problem in my opinion.

Please answer the questions you have been asked

[fourdc]

Shifty,

I've repaired a MB or two that "madman scratched with a screwdriver"

You need one of those magnifying lamps. You have to go over every inch of the MB, both sides looking for physical damage. If you find a "scratch", a length circuit land may be gone or worse bridging to another land. If the board is a multi-layer and the damage goes below the surface you probably will not be able to repair it.

If it's just surface damage, you have to clean up the scratched area. Using a small soldering iron melt a drop of solder on the iron and bridge the broken land DON'T stay on the board for a long time. Visually inspect your work to verify that you didn't bridge anything other than the break. Give the area a small dab of clear enamel fingernail polish.

If you don't have any of this equipment, it would probably be cheaper to buy a replacement MB and transfer your "goodies' over to it.

[shifty]

Im thinking that new MB is going to be the easiest answer here. Thanks for your input fellas.

[Riot]

Before you go out and by a new mb i have a few questions for you, have you installed any new hardware in to your box befor this started happening and if so what did you install and is the mouse and keyboard your using new or old.

[nihil]

Hmmmm,

1. What happens if you boot without the keyboard and mouse and then connect them?

2. What happens if you boot with just the mouse connected and just the keyboard connected?

3. Does your board have PS2 ports? if so what happens if you use a PS2 keyboard and mouse?

4. When you say that it won't "power up" do you mean that literally, or do you mean "boot up"?

5. Do you get any BIOS "beeps", if so, how many?

6. With the keyboard and mouse attached, what lights do you see when you power up?