Unfortuntely, the Dell motherboard form factors are propietary, so you'll have to buy replacement motherboards directly from dell.
$200
I'm sorry about the death of your computer's motherboard. You can find a replacement on ebay.com, amazon.com or even Dell's website. Good luck on finding a replacement!
It is often hard to fit an after market motherboard into dell computers, you would have to check the dell website.
The type of RAM that a desktop computer uses depends upon the design of the specific motherboard that is installed in the computer. Refer to the specifications of the motherboard or of the computer manufacturer (i.e. Dell, HP) to determine the proper type of RAM for your computer.
The Dell Optiplex GX620 SFF uses an F8101/0F8101 type motherboard.
Sure can....have done so...you may find the Wifi card from one motherboard or graphics chip doesn't plug into the other so make sure you get the graphics chip with the motherboard. The answer is a qualified yes. The 5100 motherboard does fit in the 1100 case and will mount with the same holes. However, you must also replace the power supply, graphics card, CPU, CPU fan and a couple of other parts. So, after having done all this you might as well have started with a new computer.
T5600 Motherboard
The Dell XPS 400 series uses a BTX format motherboard. A BTX motherboard measures approximately 325 by 266 milimeters.
Dell motherboards are designed to be different than your typical board. Even if you open up your dell PC you will see its on the opposite side of the computer then it should be. The idea behind this is that it eliminates technicians from messing around with them too much. Its their way of making sure that they are the only people who can fix them. If I were you I would look on eBay for a new one. Its not uncommon fto find people who were lucky enough to get their hands on new dell parts to sell them on eBay.
Go to the manufacturers website. Or go to the website of the company you bought the computer from (ex. Dell, Gateway, Sony).
If your warranty is still available for your laptop, you can send it back to Dell for a website. Alternatively, you can buy a new motherboard from Dell's official website.
Power supply or motherboard is bad.