Hi there, I just got a new iMac and am giving my old one to my Dad. I bought it years ago with Leopard, which I upgraded to Snow Leopard and then a few months ago to Lion from the Mac AppStore. I am wondering now, how to wipe the hard drive - and about what to do with the operating systems. Obviously, I bought Lion on my account, so with my Dad creating his own account, will I have to downgrade the OS? Not really sure what I'm meant to do now, hope this makes sense to you. Thanks for your time.