I now have my Aluminum iMac 20"... even got a new External Firewire HDD for Time Machine use. I installed Leopard with no problems.... got Time machine running on the new drive with no problem on FW. Suddenly, I can no longer access the external drive via Firewire. I can get it to mount with USB for now, but FW is obviously preferable. Like my iMac G5 in Round 1.... does the new iMac have a resettable SMU. That was the problem with the G5...but want to make sure before I try such steps on this Mac. Any ideas?!?