Thanks again, guys. And reading all your comments again I think there may be a [small] misunderstanding: My original post referred to "storage drives" [non-system] installed inside my computer. Those were the ones that I originally asked if they could be idled/powered down when not in use. And it's possible that using the advanced power options would allow me to power them down after x minutes.

I additionally have 3 e-SATA drives in open-air docks. Those drives seem to power down all on their own after 5-10 minutes of nonuse [although the docks remained lit/powered on. And of course there is a delay when I access them via Windows Explorer and they spin up.

But again, it's the drives inside the computer that I was most concerned about. Active Hard Disk Manager tells me they average 39-42 degrees -- not bad by any means, but it seemed like a waste if they'd only be accessed 2-3 times during the week. I'm assuming that it's those [internal] drives that can be idled via the "advanced power options" settings? But again, even if the answer is "yes," there seems to be a case to be made to simply let them spin happily until the computer either sleeps/hibernates or is turned off.

Again, many thanks.