FWIW, I could never get any of the later (didn't try early) developer releases of 10.5 to even install on my Cube w/stock 450MHz CPU or w/ 1.4GHz PowerLogix CPU upgrade. I'll be trying the final build (9a581) over the weekend. Bill On Oct 26, 2007, at 7:29 PM, Gary Heartsfield wrote: > Hello all > > Just tried to install Leopard on my cube with 1.7 powerlogix. > > All was fine ( 40 mins ) then on restart the cube will begin to > load and instantly power off. > > Now it will not boot from disk 10.5 > > Just powers off like the shut down was pushed, or pulled the plug. > > Can start with option key and select the HD and it takes off then 2 > seconds later act of the power was pulled in a nice way. ?? > > Any thoughts ? > > Thanks >