Shift keys constantly engaged

I recently spilled a little bit of coca-cola on my macbook pro. After having one of the apple genius' look at it, he determined that the logic board was (thankfully) intact, but the keyboard was shot so I needed to get the top cover replaced. It was out of warranty, so I ended up gettting it replaced at a third party place, and when I got it back everything worked perfectly except that it was always booting in safe mode and typing in all caps no matter what I did. We troubleshot the problem and determined that one of the shift keys was constantly sending a signal to the computer as if it were being pushed, even though it wasn't. Every other key on the keyboard works perfectly, except shift.

I can get it to boot out of safe mode by holding any key on startup since that intereferes with the shift key activating safe boot, but the constant signal from the shift key means I can't reset the PRAM or boot into the install disk to try a disk repair. A USB keyboard that I have plugged in types normally, but still doesn't solve the internal keyboard problem. Any suggestions?