I was really pleased to pick up my 27" imac today and already had bought an additional 4GB RAM to slot inside it. Took it home, opened it up and tried to remove the 3 screws from the RAM hatch. Removed the first two but the third would not budge no matter what precision screw I used. Seems the third screw came stripped and so I will have to take it back to the apple store tomorrow. think they will let me slot the ram in-store? will I have any problems with the return considering im trying to upgrade memory? I have not switched the mac on at all.