From the discussions we had I conclude that installing a switch that powers ON and OFF the +5 and the +12 is a very safe way to operate, provided the switches are only operated when power is OFF.
I have looked at my BIOS and I can't see any indication that will allowe me to power OFF any of my hard drives.
Let's face it,computers are made as cheap as possible and reliability is expensive. A hard drive lasts longer if it isn't running.
Thanks
Vlad