Got an original Intel Core Duo iMac. Last few days I've had trouble starting up the computer. When I hit the power button, I hear a weird clicking noise for a few seconds, then it sounds like the HD is powering down and then powering back up and the clicking noise again. If this goes on for ~30 seconds, a flashing folder with a ? shows up where the Apple logo should be. If that happens, I've powered it down and tried turning it on again. Seems to work, but this has me freaked out. Does this sound like the HD is dying? Also recently, my Superdrive is spitting back every blank DVD I put in there.