In general you can bring up the device manager and check the "Power
Management" tab in the device properties dialog to find out whether the
device supports any power save mode (aka idle-detection or selective
suspend) and enable that. That's the only way to selectively power down a
device. I think video cards and monitors use a different mechanism. Read
http://support.microsoft.com/default...;EN-US;Q324347.

--
-Eliyas
This posting is provided "AS IS" with no warranties, and confers no rights.
http://www.microsoft.com/whdc/hwdev/driver/kb-drv.mspx