You need to use something like a bent paper clip to start lifting the LCD off. At this point, don't rush to lift the LCD up completely--you risk damaging the connected cables. Slowly lift the LCD, enough to reach in and detach the four cables that connect to both the motherboard and the back of the display.

After the cables are detached, you can lift the LCD completely and remove the display. Finally, you have access to the hard drive and other internal components.

When reassembling the iMac, make sure to avoid getting fingerprints and dust on the glass screen cover or the LCD itself.

Not intimidated by taking apart your iMac? Still interested in do-it-yourself hard drive upgrades to the iMac? Well, last week an issue with the 2011 iMacs that might finally dampen your enthusiasm.