You do that that PS2 keyboard on that old PC, not a USB one

Whilst using DBAN to clean down some very old PCs for disposal to new homes at good causes I hit a stupid gotcha.

I booted off the DBAN CDRom but could not continue beyond the first screen as it did not detect I had pressed the return key.

Turns out the PCs were so old that, though their BIOS allowed USB keyboards (and I could enter setup and edit BIOS settings with a USB keyboard) the Linux kernel on the CDRom could not detect them. Once I switched to an old PS2 keyboard it all worked fine.

I found the same problem when putting Ubuntu onto same PCs; during the install I had to use a PS2 keyboard, but once the install completed it was perfectly happy with a USB keyboard.