I just replaced the dead hard drive in my 2008 white 13" Macbook. Apparently because I didn't tighten the little screws on the hard drive cover frame, or just being sloppy, I managed to shove both of the rubber 'bumpers' or 'rails' that are glued to the side of the drive enclosure. After trying to tape them to the drive enclosure, I gave up, as I couldn't get the drive the seat properly, and simply installed the new hard drive without the bumpers. The Macbook now works, and doesn't make any horrible noises or vibrations.
I am wondering if it will be safe to continue to use this laptop with its missing rubber bumpers, or if I need to take it in for a proper repair, and have the bumpers replaced or re-installed. Does anyone have a knowledgeable opinion?