After performing the required restart following the update, my iMac G5 froze before it could launch the finder, and initiated a high fan rotation (usually my machine is dead quiet). Subsequent restarts yielded identical results. Left unattended, startup will progress as far as the login screen before freezing. If I respond immediately to the login prompt, startup will get as far as painting the desktop background picture.

I used the Tiger install DVD to select my backup partition as an alternate startup disk. This worked fine. AM I alone in this?