Recently my normally stable iMac has been acting erratic. When ever I am saving something especially apps like iTunes, or using flash it just beachballs for 5-10 seconds. I also had my Hard drive disappear for about 3 days, where It wouldnt boot up and was unavailable as a boot up option. Does this mean my Hard drive is failing, or do I just need to re-install Snow Leopard? Is this a reason I can get the Hard drive replaced through applecare? One cause for this change in my macs behaviour is that I have recently been editing/recording a lot of HD content.