Save Power from the BIOS

Most PCs have advanced power-management features, which can be controlled from the BIOS. Once inside the BIOS, hunt for the Power option, and enable it. Usually, you’ll find a default and a user defined option. Once enabled, you can set the inactivity time after which your hard disk and display will power down.

However, this feature will not work for SCSI drives, as they have their own BIOS.