Identifying form factor

Ok, I need help finding what motherboard will fit in a case. I was given a Dell Optiplex GX240 (vertical tower) with a few working, and a few broken parts. The motherboard and processor, are two broken parts. I know a little about the hardware side of computers, at least enough to put one together (not like that shit's hard), but I don't know form factors. The broken motherboard in the thing is a '62YVH REV A00'. I've searched for that and the computer's model every which way I can think of and I can't find the info I need. Sorry if this seems obvious to a lot of people, but I guess it's that much easier to answer. :)

Thanks a lot.

basicly there are about four formfactors that are availble today
AT/XT (realy old and big, this is not what you have) ATX (the most commonly availble standard today) MicroATX (smaller :) and Mini-itx.
There are also a couple of variations of the above, like ATX 2.0 12v ATX that have minor differences.
Most of these variations do however use the same basic layout (position of screws and ports).

However dell computers suck when you need too replace/rebuild your computer since they use thereown standard.
take a look at this picture:
http://i18.ebayimg.com/02/i/07/4e/13/a7_1.JPG

if that is what your motherboard looks like, you probably have a non standard formfactor.