My iMac (17" C2D) has been my workhorse for the last 3.5 years. This morning, it too an age (over an hour) to get any response after booting up - constant beachballing in numerous apps. The RAM had no page outs, and there is 30GB free on the HDD (160gb). I bought TechTools Pro hoping that it would help me diagnose the problems. I ran a surface scan and I have 10 bad blocks (out of 312,581,808). Does this mean that the hard drive is kaput? What does everyone advise I do? Appreciate any comments or tips.