My G4 has recently refused to Restart or Shut Down from the Apple menu. All the applications quit but I am left with the blue background and have to press the power button and hold down for a few seconds until it switches off. [the volume also sets to mute when I re-boot] I can get it to sleep using the Apple menu or the power key on the monitor. It only appears that the Restart and Shut Down which are the problems. I have tried... resting the NVRAM & PRAM -battery reads 3.7v [cmd-opt-p-r] [cmd-opt-n-v] reseting PMU (power management unit) removing and re-seating the memory removed all unnecessary peripherals run Applejack for Tiger run TechTool Pro v4.0.4 run DiskWarrior v3.0.3 started up in Safe mode I _may_ have tried other things but just now can not recall. I am unable to say when this problem was created as my machine is normally on 24/7 and did not come to light until I was forced to re-boot after installing some software -and yes I have checked it. Could it be the upgrade from 10.4 to 10.4.1? Any help/ suggestions much appreciated. [System- macintosh G4; OSX 10.4.1; 1GHz; 896 Mb SDRAM] -- -- Peter The box said "Windows '98 or better", so I bought a macintosh.