motherboard

It may or may not be easy to find.
If you have a name brand system (Dell, HP, Gateway) go to the mfg web site, and get whatever information you can.

Otherwise, try using an information utility such as Belarc Advisor www.belarc.com or Sandra fromSiSoft.

Look at the motherboard, and see if there are any markings for make and model.

Watch the boot screens. Some MBs display make model and BIOS revision while booting.

The fianl check is to copy down the BIOS string that is near the bottom of the screen whhile the memory is testing.
Go to either www.wimsbios.com
or www.motherboards.org
From the BIOS string, you can identify who manufactured the board. Then, you can browse through their web site to find your particular board.
There are also a couple of articles on this in the TechRepublic archives.

Follow these clues to find a motherboard's manufacturer

Nov 27, 2001
Van Glick

Keep your motherboard up to date

Dec 3, 2001
James McPherson

I have foundit best to use all lower case for TR searches.

Chas

The BIOS string is the easiest, followed by the FCC ID. (Assuming the motherboard has no other markings, common with cheap Chinese motherboards.)
Regards, Chris