Changing hard drive on imac 7

> Bit awkward. Thanks to video (http://www.youtube.com/watch?v=2YsCTNVEYt8&noredirect=1) it wasn't so bad but why did apple not just have panel on the back? Applestore 'genius' said the most awkward bit is the making sure there is no dust in between the glass and the screen. He is right I'm looking at the dust as I type. Apparently doesn't matter what type of drive you use just 3.5 but i ended up using 1TB seagate barracuda opened up mac and found old one was a 250gb seagate barracuda. Dandy