15 - 30 minutos
Internal 5400 rpm 500GB hdd failed. Had flashing folder with question mark, disk utility could not repair drive. Purchased 7200 750GB replacement.
Used ifixit free ipad app for instructions, with the tools that came along with it. Very easy repair, instructions were very straight forward. Disk utility immediately recognized the drive and was able to format it. Finally upgraded all the way to Lion.
Make sure to take the bracket screws off the sides of the old hdd and put them on the new hdd so that it will seat properly in the bracket arm that holds it in place.