Called Dell Support and they unlocked the BIOS. All OK!!
BIOS 1.14.1 I'm a resident of a retirement village and after one of our residents passed away, his wife decided to use his laptop but he hadn't documented the password. She brought this to me because I can help with simple IT problems. From what she knows, this is an ex-government laptop purchased from somewhere. Anyway, I said I would load up a fresh copy of windows to which she can create her own password. Then I find that I can't set it to boot from a USB because the  BIOS is locked. I guess he never had to go to the BIOS or he set it and didn't document the setting. She is a pensioner and can't afford another PC, so how can this be resolved?
Locked BIOS