Thanks for your reply.
I still cannot cannot get into Safe Mode with Networking or get F8 to launch Safe Mode (I have entered the Command Prompt Admin).
1. Networking. I select 'Safe Mode with Networking' ---- as soon as the network icon appears it shows there is no connection, followed by a notification that there is no connection. If I then try to connect or if I try to diagnose the connection it says this cannot be done while in Safe Mode and I must reboot. This was the same when the OS was W8.1. I have never been able to launch SafeMode with Network, something of a handicap.
2. Using F8. In the article for which you provide a link there are important basic steps omitted, not helpful for a newbie or in my case someone who has forgotten the procedures years ago ---- such as at what point do you press F8, immediately after entering the password? presumably you use both the Fn and F8 keys together? (I have tried it with and without) do you hold the key(s) constantly until in SafeMode or, as I seem to remember, keep tapping the F8 key? Either way it does not work.
The procedure takes so long one is inclined to think it is failing and stop the action before it takes effect.
Clarification will be greatly appreciated! In the meantime I will keep trying.