I have read several posts on this problem although they all seem to be able to get to a boot screen or some type of screen. The only thing that I get is the Fans (AC power and Heatsink) turning on, no normal beeping or churning of the HDD's. The monitor stays in power save mode, no keyboard, no mouse activity. I can not get anything to come up.

The computer is fairly new (6months), I had orginally 256mb RAM, 60 Gig, Athlon 2400+, and onboard video card. Throughout the course, I have put another 512MB, 250 Gig HDD, and a Nvidia 5600 FX Ultra. The computer has been working perfectly for the past 4 months with all of the added features.
The only questionable thing that happened was last week; went to the store, came home and the computer had shut itself off. Turned it on and thought nothing of it., two days later, samething, but this time had to wait for a couple of hours for the computer to boot up properly. Then yesterday, it shut off and now nothing. I have unplugged for several hours, took off the side to let the PC cool, still nothing. Would unplugging the MOBO battery do anything?

I am stumped, I think it may be the Video card or the MOBO but I am not sure, I would rather have you all take a look before I invest any more money into this thing. Sorry for the long post, ladies/gents.

Removing the motherboard battery for a few minutes and then putting it back in (with the mains power disconnected of course) is a good thing to try as it costs nothing and is quick and easy. The point of this is to reset all of the BIOS settings back to the factory defaults. Bear in mind, though, that this might mean that you'll have to go back into the BIOS to get some things to work as they used to. As there are so many different BIOS setups and none of us can see any of them whilst we're in Windows, it will be difficult for us to help you with this if you get stuck.

Unfortunately, in my experience, I've found a wide variety of things can cause this problem - grpahics card, motherboard, processor, memory and, more recently, I've found that the power supply is the culprit surprisingly often - in fact, I'm just about to fix the same problem in a PC I'm rebuilding here by replacing the PSU!

"The point of this is to reset all of the BIOS settings back to the factory defaults. Bear in mind, though, that this might mean that you'll have to go back into the BIOS to get some things to work as they used to. "

How would one find out what the original BIOS settings were?
Could I take the power source out of an older computer and attach it to mine?

I will disconnect the battery tommorrow, (not currently at my house right now), hopefully this will work. If the bios is reset to something that will not work then i am not quite sure how to get one that works. i am basically a software man, hardware on the other hand is basically new to me, except the basics. Thanks for the info so far DJNafey.

Disconnecting the mains electricity cuts off the power to the system but the motherboard battery still runs so that it can remember the BIOS settings (such as the clock, which doesn't stop counting just because you've turned the PC off). When you disconnect the battery, it forgets all of that as well.

When you re-connect the m/b battery and switch it all back on, the BIOS sees that it has forgotten everything and then automatically restores the factory default settings. If everything appears to work OK after that, simply change the date and time in Windows and you should be able to carry on as normal

Thanks DJ, I will do that later on today and keep you informed of what took place.

Well, I am now writing this from "my" computer. Worked perfectly DJ, thank you so much!!!!! for the help. Talk about a true money saver, who knew it could be that easy. Thanks again. Is there a way to donate via snail mail?

Sure is I've PM'd you.

Thank you D-A-L, I will definitely get that to you all.

But.....The problem that I thought that we have solved has begun again. I have tried everything that I thought was possible. I MultiMetered every wire that I could think of (both HDD's, DVD, CD, Video Card) Everything checked out OK, I swapped the Ram, video card with my Roomates, with each time taking out the MOBO battery, still no *boot* up, the screen still remained blank. You could hear the HDD's getting power with the normal wining of the disks. I then took the 2 HDD's out of my computer, and placed them in my friends PC and everything booted perfectly.

The only thing that I can possibly think is that the MOBO is fried.

What do you all think?

does anyone have any ideas??? I would rather not have to buy a new MOBO.