[eliot1164]

My faithful old Dell suffered major problem so returned all to factory settings. Now working well again except that the number1 ! Key is inoperative. Have checked the obvious physically, no debris etc. Is there anything I can do myself or is it the bin for my poor old machine at last.

[npb575s]

You could try reseating the keyboard cable to the motherboard other than that I would say probably replace the keyboard.