If you fit a new hard drive, it just automatically tells you you have a new hard drive and then keeps on loading windows. Thanks, Robbie Robbie, To get into setup, you have to press the F10 key precisely when you see a blinking white square on the upper right corner of the black bootup screen.
Timing is everything.
This is strictly for Compact, for other makes see the link below. For you second question, I can't believe there is no reset. I've seen some that were so small, that you had to push it with the point of a pencil. Not that I don't believe you, because I've seen some weird thing done to computers. If you fit a new hard drive, it just automatically tells you you have a new hard drive and then keeps on loading windows.