Lately almost all the XP machines in our office (15 out of 18 computer) will shut down instead of rebooting. It doesn't seem to matter how the reboot occurs. Examples: 1. Windows needs to reboot after an update. Click reboot and the machine shuts down.. 2. Install new software or antivirus. Click reboot when asked. Machine shuts down. 3. Windows automatically reboots after automatic update. Machine shuts down. 4. I select reboot from the menu and the machine shuts down. This is really annoying as I have maintenance scheduled each evening and over half of the computers are now off following an automatic update. I also use remote sessions to check on machines. Now I cannot (at least not at night). The problem doesn't seem to be machine specific either. We have Dells, Compaq's Toshiba's and white boxes and most will shutdown instead of reboot. I've searched Google for three hours and almost every post addresses the OPPOSITE problem (reboot instead of shutdown). I don't have the specific CD burning programs on my machines (as one post suggested) and all virus and spyware definitions are up-to-date and not reporting problems. For the moment I've changed automatic updates to "Notify only" and not to install anything unless I am physically present. Anyone have any suggestions? I'm really baffled.