Two things I can think of :
1) The broken plastic in the power receptacle may be a reason for the power lead to not make full contact on the screen's board thus not providing power (yeah wild guess I know

). Have you tried to move it with your hand?
2) Can the other buttons be pressed or they're on-the-air ? Could be a problem with the button/ir sensor PCB got out of alignment causing a short circuit or something.
I believe you should open it up. No one will buy the screen without knowing what works and what doesn't. If the vga controller board is fried, $250 just for a (hypothetically) working touch controller are a lot of money don't you think?
See ya