Hi, I'm so annoyed regarding the broken Entourage <-> Exchange SSL root cert situation that I feel I must let others know of the following... To perform a fresh / clean installation of Mac OS X 10.5 Leopard to a totally blank/formatted hard drive using nothing but the upgrade DVD, do the following: 1. Boot from the Mac OS X Leopard Upgrade DVD (hold 'c' while booting). 2. Notice that the check for previous will fail (and "Continue" button is grayed out). 3. Choose the option of restoring from a Time Machine backup and go as far as you can (note: if you do actually have a Time Machine backup, pretend that you don't - making sure you've already removed any backup drives you may have plugged in). 4. Now go back to (almost) the initial screen. 5. Notice the "Continue" button is no longer grayed out... 6. Install Leopard while drinking a beer.