You have a "Gen 1" Segway, last manufactured sometime in mid 2006.
I'm not particularly Gen 1 knowledgeable, but more than likely, the issue is the batteries. Batteries MUST be kept charged as the Segway is pretty judgemental about charging batteries that are below what it considers minimum voltage. Also, old batteries lose their capabilities and may not charge, If the batteries are not good, the Seg won't charge and won't let you ride.
The batteries are the single most expensive components in a Seg. I suggest you try to contact MTOBATTERY or DGBINT on this forum for the details about how to check your batteries, and what your options are.
Here's a link to the manual
http://www.segway.com/media/1921/gen...encemanual.pdf