I have G4 AGP (450Mhz) which I have just upgraded with a Sonnet Encore 1.8Ghz processor and I have been running it ok for about a week and a halve with tiger 10.4.11 with all the latest updates and all was fine working great. I did a upgrade with Leopard last night and all went ok no error mesages or it saying that my machine was not supported it finshed installing ok and then rebooted and it got as far as the gray screen and the apple and then shut down. Tried rebooting several times and stll the same. I was able to boot into 9.2.2 on another disk installed and it was ok., it was getting late so I switched every thng of and I was going to have a look at it the next day when I came home from work now it won't switch on at all now dead as a Dodo. I know there's power because my monitor is plugged into the same power supply and that has the power light on. anybody got any idea's.,