Erase Hard Drive on 540c

Macintosh

I have 2 old 540c powerbooks. I would like to erase the hard drives and get rid of them. When I power them up I get a screen that says that they weren’t backed up since 1997 and it won’t let me go any farther. Is there any way to format on startup. I am sure that there is a key combination, but it is so long since I have used them that I forgot.

Regards, Steve Pollock srpollock@yahoo.com