: Thanks for your reply
You are welcome. I am sorry about this mess, but I really don't know how it has happened or what I can do about it.
A colleague in the IT department in the company I worked for thought it might be some sort of virus which has created the chaos, but if so I don't understand how it has happened, as I certainly haven't clicked on anything I shouldn't have, and my virus protection program has not reacted to anything.
So I don't really know what I can do about it. Any experts out there are welcome to contact me privately at dagtho[at]yahoo.com.