Thanks, all. Problem identified, if not solved. Garth: that link identified the problem. When I downloaded Ubuntu back circa 2006 onto a PC using Windows something or other, all it took was to click on the download button and follow the instructions; the process erased Windows and substituted Ubuntu. I expected to do the same with this old Macbook but, apparently, with Macs, damn Apple's eyes, it is hardly as straightforward.
Hopefully the video technique will help. "Apple’s made it difficult to boot non-Mac OS X operating systems off of USB drives. While you can connect an external CD/DVD drive to your Mac and boot from standard Linux live CDs and USBs, simply connecting a Linux live USB drive created by standard tools like Universal USB Installer and uNetbootin <http://www.howtogeek.com/191054/how-to-create-bootable-usb-drives-and-sd-cards-for-every-operating-system/> to a Mac won’t work." -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.