For some reason the past couple of days my iMac is acting weird. Lots of programs are hanging up, my mouse will stop working randomly, comp will lock up when I try and take it out of screen saver, firewire 800 drives arent recognized, now my time machine drive isnt showing up. I recently got 2 new Buffalo Drives but I wouldnt think that would cause problems. Is there anything I can do to check my system or do a scan disk (i know on a windows machine there is defrag, disc scan etc). Any help or experience with something like this would be very helpful!