Replaced failing hard drive on 21.5" iMac

Mi Problema

The existing 500GB internal drive on my late 2009 21.5" iMac was developing an increasing number of bad sectors, and was probably close to failing.

Mi Solución

It was quite easy, and took less than an hour, with the proper tools.

Mi Consejo

Use a tweezers or small pliers to help extract and insert the Torx screws that attach the display to the case. Otherwise, you risk dropping the screws into the case, which means you'll have to remove all the screws and lift the display in order to retrieve them.