fihart: tks a lot, i was actually in search of that kind of software but unsuccessful yet. there is no such option in BIOS, it has just the option of running processor in dynamic freq. range to save power.
steadfast1984: actually, with hibernation and screen saver, we cant 'use' the computer. what i mean was to use the computer with hard disk off (of course for things not requiring hard disk file access, and somehow manage for things the operating system tries to access hard disk). tkx