Arduno Mega 2560 not working

Hi there, so here I am at work, and they've given me a few Ardunos to play around with. Now theres 1 uno that works fine but I got to the point that my projects use more pins then the uno has to work with so I grabbed the Megas. 1 of the megas works fine. The other however won't take any program I try to upload to it. It just sits here with the little onboard pin 13 LED shining at me. I was wondering if this was because the board itself is shot, or if there's some easy fix I can do to counter this.

You could try re-burning the bootloader.

Perhaps, umm how exactly would one do that?

Do you have or have access to an ICSP programmer or an Arduino Duemilanove?

If you don't have an ICSP programmer and intend to be in the AVR microcontroller sport for a while, I'd strongly suggest getting one. They can be bought for $10 (Plus shipping) and are (I think anyway) indispensable.