Can anyone suggest what might be causing this. My old Quicksilver G4 power supply went wrong, so instead of paying a fortune for a new supply, I purchased a 'bench tested' second hand QS from a mac dealer. I have swapped over the 2 HD's from my old QS to the new one. All went well (thanks to those who helped with how to do this) and the computer worked fine. Only problem is, when I put the QS to sleep using the sleep key from the apple menu, it won't awake using key or mouse movement, in fact, I have to force quit using the display on/off button, which obviously is not good. Now I've checked all the energy saver settings, they all seem to be fine, so I cannot see what the problem might be??? Can anyone help?? Many thanks Graham