Dell Optiplex 7040 Motherboard with no CPU or memory. Was working when I pulled it from a working machine due to password lock on the BIOS, preventing me from making any changes. Unfortunately I was unable to remove the password (methods are described on the internet), but maybe that was because of my eyesight deteriorating due to age, and I could not locate the jumper on the motherboard.
Update on Monday 11May: I found the jumper, just to the center below the Blue PCIe connector on the photo of the motherboard! Shorting it will clear the CMOS lock.