I run a network of about 200 clients with a Windows 2003 Standard Server Active Directory.
This server also runs WSUS.
The machines are configured to install updates at 5pm every day and then at 6pm each day, the server runs the following script to shutdown all computers:
shutdown -m \\computername /s /t 90 /c "Automated computer shutdown for preservation of energy. Please save all work immediately!"
I have found that sometimes computers whose monitors are already off, or screensavers are perhaps on (not always though) - they will not shutdown when the command is sent. However. When I go up to the machine and move the mouse, it then shuts down and reboots!
I'm not sure whats causing this exactly - if anyone can shed any light on it, that would be great.