[G4] G4 Cube Upgrade to Leopard

[Abraham Bloom]

Good Morning,

	I have a G4 Cube that I have tried to upgrade to Leopard.   It has a  
Sonnet Encore ST 1.2 Ghz Processor.  It booted and ran the entire  
installation with nor problem.  Upon completion and reboot it shows  
the grey screen with the apple and POWERS OFF.    I have tried to load  
it from my Powerbook G4 1.25 ghz with the Cube in Target Disk Mode  
with the same results.   Thoughts?    The cube has 1.5 GB memory and a  
120 gb Hard disk.

Thanks
  Abraham