Dear Lonnyb23,
The Surface Table has a PC in it. It has quite normal components, so yes you could build a better one than the original.
The only three things that aren't normal are:
1. The computer case, that has an od shape, but could be replaced with something smaller that fits the space offcourse.
2. The PSU has a power outlet speciffically designed for the beamer that is beaming the image to the tabletop.
3. There is an PCI card to connect the rj45 cables to that is for I think the (power to the) touch capability of the tabletop, that's done with camera's.
So yes it can be upgraded or in your case fixed to get working again, but not (easily) without the original PC unit that was in it.
Question: Did you get the original software and OS disks with it, because I need a copy, because the HDD in my unit crashed.
Greetings and happy holliday wishes from the Netherlands.