You can't manually turn off your HDD permanently in Windows, probably the only way is by unplugging the power cable. That power setting allows the HDD to spin down if it has been idle after x mins that have been set (allows the magnetic head to rest and overall consume less power).

However, if you are BT-ing or running any programs that frequently read/write to the HDD, your HDD will almost never spin down (or for only brief periods of time before having to spin up again) and that power saving setting would not have any effect on a whole.

This post has been edited by shockw@ve: Jul 26 2006, 04:59 PM