Originally posted by: Lord Evermore
During installation, you must select ACPI Computer as the system type. If you don't, then the ACPI drivers aren't installed and some options like that may not be available. Look in Device Manager, and in the Computer type see whether it says it's an ACPI computer.
You may also just need to enable it. It's in the Power options available from the Screensaver tab of display properties (stupid place for it of course).