I just recently purchased a refurbished 24" iMac 2.8 C2D with 2 GB RAM because of a failing harddrive in my 4+ year old Powerbook, although at times the iMac acts stranger than the Powerbook! I often find myself pressing the power button on the back to shut it down because apps are unresponsive (or when doing software updates, apps failing to quit). This happened again just 5 minutes ago (because the system froze when I tried to log on to Adium); the restart process has already taken a few minutes and there's nothing but a white screen. I hate to say it, but this new machine has already been more trouble than I'd imagined and I don't see it getting any better. Could this be the result of it being a refurbished machine (I see this as unlikely)? Any steps I could take to remedy this?