I have a fried motherboard on a Dimension 8100. I do not even know where to start to find the correct board for it and it seems that Dell makes it especially difficult to replace. I called for a Dell price and they wanted $299 for one that will work, but not the same kind as is in there now. Any thoughts or advice appreciated.

I'm afraid you're in a world of pain trying to chuck an of-the-shelf motherboard into your Dell case. AFAIK, the connections on the power supply are proprietary for a start.

You could perhaps get a new motherboard and a new case for close to the price of what Dell wants to charge you for a replacement board.

You could use re-use your current drives and graphic card (I am assuming that these are not on-board devices in the 8100). And at a push re-use the memory (as long as it's not of the RamBus variety that is).

Can you supply the specifications of the machine?

It is a Dimension 8100 1.3 ghz, 256 RDRAM, 64 GeForce video, Santa Cruz sound card, 60gb HD. I have found a new Dell mobo on E-bay that fits the Dell part number. I can under extreme duress change out computer parts, but never as sophisticated as a motherboard. I have looked at some other posts on this board and it seems that Dell makes it as difficult as possible. I thought if I could get the board off and just replug everything else back in, it would be okay. Now, I am not so sure.

If your Dell came preinstalled with Windows XP, I would not recommend buying a replacement motherboard from any other source, and here's why:

The way Windows XP is installed (and thereby activated) the activation string is in the system BIOS, and you would not be able to reinstall Windows at all, since it would assume you were installing on a non-Dell system.

Sure, you could try to circumvent that, but if you have a legal license for it (which you do if it was preinstalled), there's little reason to do so.