I tried taking out the L shaped bar today to replace the RAM in my MacBook. The first two screws came out really easily but the last one seemed to be stuck. So I tried turning the screwdriver really hard and I though I was unscrewing it but it looks like I stripped it. So now I'm screwed (no pun intended). So what should I do now? Should I bring it to an Apple Store and tell them to unscrew it and give me a new screw? Would they be able to do that on the spot? Or wil they refuse to do it because I'm intending to install 3rd party RAM? Please help. Thanks.