Well, is the processor still intact?
If so, what is it? You can't just buy any motherboard.
Also, I hope you are talking about a desktop, because for a laptop you might as well buy a new one.
Just a little more information would help.
First off know what processor you have and socket...
Decide if your going to buy new ram or not, if you aren't check the speed and find a motherboard compatible...
if you aren't look at new ram speeds like DDR2, chipsets...
Btw if you have an old AMD with socket 939 they no longer make moabs for it. You would need a new processor.
My mainboard is burn due to the faulty of the power supply. I'm now looking for best the MB at the low price range.
Any suggestion?