My computer boots great - no problem. However, I can't get the mouse to work. Its a PS 2 and it won't do anything. I took the computer apart, dusted, connection, pins, everything seems fine. What could be wrong?
When I had it apart - I was checking if it was plugged in entire way and it did reboot my computer. HELP???

I would highly suspect a short in the mouse wiring or a problem with the PS2 port on the motherboard.
If someone has a PS2 mouse they would loan you [or buy a cheap generic mouse], plug it in and see if it works, if not it's the port.

Maybe a silly question - but can I change just the port or am I looking at a new board?

You could get a USB mouse, a very common setup now.

   If the problem were in the port connection itself, you would be able to replace the port depending on how mechanical you are.  But the problem (if it is not the mouse itself) is most likely in the motherboard which would require the replacement of the motherboard.