I have a 3 year old machine, that is built around an Intel D845EBG2 motheboard. Recently, during a reboot, the machine booted, but with no video (the video card is an AGP card from nVidia).

After checking the obvious - display plugged in and on, connected to the PC (reseating all connectors) I tried again and it worked, booted the PC and then shut it down to try again - no luck, no video.

So, I opened up the case, re-seated the video card, tried again - nothing. Eventually I pulled everything - network card, modem, HD, CD, Floppy, & memory.

I then connected only the video, keyboard and booted the PC. PCcame up, had video and I jumped into the BIOS setup so that I could get full reporting of the POST during boot up (was set for Quiet). Saved my settings and tried again. No luck.

Reseated the video and memory, turned the PC (I removed AC power every time) on and it booted. Tried again. No video. Disconnected AC, waited a minute or so, reconnected AC and turned the machine on - same results - no video.

So, turned the PC off, disconnected AC, pulled the video card only, repeated the test...no video.

Next, I pulled the video and memory, reseated them. started up and there was video. Tried this approach several times and it worked. Connected the HD and booted complete into XP. Shut down and tried again, without reseating anything - no video.

So, after all this, I can get the PC to boot, with video, if I reseat the memory (256 M DDR 200) and video. This does not work if I only reseat the video card. Because of physical interferrence I cannot reseat the memory with pulling the video card.

Now I am stumped - is the problem the memory, the motherboard (or the video card)? This machine has been running for 3 years, used by my daughter. Any thoughts, suggestions, would be appreciated.

Try replacing the mobo battery. The little button-cell CR2032. A bad mobo battery can cause odd problems like this. Make sure the old battery has been removed for about 10 minutes before inserting the new battery. This will erase all data in the CMOS, which means resetting all your BIOS settings, but it makes sure all the data is "clean" so-to-speak.

Also, it seems that reseating can make a difference. Try cleaning your vid card and memory connections with a bottle of 91-97% Isopropyl alcohol. I usually clean them reseat them, clean them, reseat them, etc - several times just to make sure. The older the system, the more times I repeat. This works wonders if they've never been cleaned!

Try these two options and report back. Then we can check and see if these low-level maintenance tasks make a barebones boot more successful...

Also it comes to mind since rond36 posted to the thread today. Check for bulging or leaking capacitors while your inside the box. Bad caps can cause such odd problems as well.
http://www.pcguide.com/vb/showthread.php?t=25482

Also, run Memtest86 to check the RAM with only 1 RAM module installed at a time.

Well, I tried a new battery - no change. I also have cleaned the contacts using an eraser and alcohol...no luck either.

I have inspected the caps...touching every one- none seem to be bulging or leaking.

Even pulling all memory and booting, no video. At this point I really suspect the video card. Is there any reason that I shouldn't?

Even pulling all memory and booting, no video.If you removed all of the RAM, then there will be no display. Or do you mean something else? Did you run memtest86?(it runs off a floppy)

I need the link to memtest86 I would like to test my memory too

Here:

http://www.memtest86.com/

Are you getting the proper beep codes as you remove the vid card and RAM? And you've disconnected all drives for these tests?

At this point, you might want to try your vid card in another system. If it works, then your mobo might be the problem. If not, the vid card (at the very least) is dead.