My mid 2010 iMac has been acting up recently. When I turn it on or wake it up from sleep, the hard drive makes loud clicking noises. It crashed a month ago and I had to erase the hard drive and reinstall Lion. It also seems to be lagging a lot and often gets the beach ball. That being said, it passes the hardware test, and shows no problems under the Disk Utility. Thankfully, I got the extended AppleCare warranty. If I were to take it in to the genius bar, would they fix it or tell me nothing is wrong with it? I just don't want to lug this 20 pound behemoth in there just to be turned around.