My Intel iMac (2GHz Core Duo, 2GB RAM) has been painfully slow and unstable after updating my computer (some security update, I think). After the update, Mail locks up, takes a while for my desktop to appear after login, iChat and Safari crash when I start them, takes 4+ bounces for an app to start. My iMac has gotten slower over lots of usage and partitioning (from Boot Camp). I'm going to back up my stuff, boot from the DVD, repair the hard drive and do a clean install. How can I avoid having this happen again? I want my Mac to be as fast as it was when I bought it. Any ideas?