No the numlock action did not clear the problem. However, when the numlock was on, I found that blue Fn numbers 1, 2, 3 and / worked on my test spread sheet.
Would attaching another key board, via a USB socket, solve the problem?
No, the white key numbers, on the top row are the ones that I use most, are not working either.
Yesterday after a complete pause in use for 2 days. The last use was on a Lotus spread sheet, followed by a brief on line session to update the Bullguard internet security and running C Cleaner to clean up junk. Usually follow this procedure and I did not notice anything untoward.
Restore did not work and so I manages to get a usb stick full of data back up. I will move all Lotus to open source Libre, eventually correct my files to work on the Asus. In the meantime the ex desk top, MS 3000, via the usb connection works fully and will enable me to sort my accounts for the tax returns.
Many thanks for your help and I will contact you again if the problem gets in the way again. I may be retiring but I will have to keep up with computer developments.