That was OK but then I wanted to format the problem drive which I did on another system. This system also has two drives, one with the operating system on and one with files on it. When I had formatted the problem drive I replaced it with the drive which was there before and is full of files. I now find that this drive is inaccessible yet nothing has happened to it apart from disconnection and reconnection. Of course the drive I had formatted had taken its place for a time.
I have given the drive the same letter identity as it had before but if I try to access it I am told that this drive is not formatted, do I want to format it? If I click on properties it shows as 100% blue showing no free space and also no used space and no capacity?
Does anyone how to correct the problem so I can access this drive? Thanks.