Shift Key stuck on.

I saw a similar post about this problem but I am running on a MacBook Pro and can give more detail. The computer went through the problem of being stuck with the shift key forcing it to start in safe mode. Took it to an Apple store, found out the warranty is expired and they did a PROM wipe to try to solve the problem. Take it home, then the harddrive is corrupt and wont even start up anymore. Finally got the install cds, wiped the whole hd clean, and started over. Shift key is still stuck in on, so I removed the keys completely and it's still on. The shift key randomly turned off after I had turned it on after it died from the battery and allowed me to enter my registration info. I'm currently installing software updates, hearing that if its software that might fix it. Anyone know what might fix this problem, or help determine if its not the hardware its self. Price for a new top layer unibody is 300$ and I don't have that kinda money.