The disc came with my iMac, but I've resisted the urge to upgrade until now (10.5.2), partly because I wanted to know what Tiger was like (this is my first mac ever) Any tips you can impart before I attempt this? I've read some stuff about "repair your hard drive and permissions before installing." What's this all about? I don't have any real critical 3rd part apps other than the Adobe Creative Suite. Am I cool to just pop in the disc and click 'upgrade'?