I'll be passing on some computer equipment shortly, including hard drives. Can anyone tell me whether a full format (as opposed to quick format) overwrites data sufficiently to stop someone else recovering it?

I had thought of inserting any boot disc, vista or xp or whatever, and going as far as deleting the partitions and then formatting the whole drive, before cancelling the rest of the install. The drive would still emerge formatted?

There's a hidden partition with recovery data on one of the drives (my Dad's), I'm assuming this will show in a boot disc? I don't see how else I can do it, I could scrub data but it would still leave Windows on the drive and I'd never be able to erase the partition containing Windows from within Windows.