How do I identify what motherboard I have?

When assembling a computer, you need to know how to set the jumpers, and to know what type of memory and CPUs it supports. This is difficult when you have a second-hand board and no manual.

The first thing to do is to have a close look at the motherboard and find the manfacturer name and model number. The model number is usually a short, aphanumeric string such as 486-PV/I or P55IT. 486 boards will often have "486" in the model number, and Pentium boards may have "P54" or

"P55". If you found the manufacturer name on the board, you can go to their web site and usually find a manual, or at least a summary of jumper settings. If you only found some candidate model numbers, it's time for more detective work.

I always start with doing a web search for the model number (http://www.altavista.com and http://www.hotbot.com seem to work particularly well for alphanumeric text searches). There is also a search engine at http://www.motherboards.org/ for this purpose. These may point you to the manufacturer web site directly.

In the case your motherboard is pre-web and the manufacturer has no copies of a manual or they went out of business, there are a few collections of motherboard manuals on the web. 

If the computer boots already, you'll be able to find the model or at least the manufacturer by looking at the BIOS ID string that comes up on the boot screen. This is a long string of letters and numbers that may take a few tries to read (try adding a boot delay if you need time to write it down). A database of motherboard model numbers based on the BIOS id string can be found at: http://motherboards.mbarron.net/tables.htm