Thanks so much. I misunderstood your first post, but now did it as you advised and it is all working perfectly. Really grateful for your help.
Eamonn

The lastest state of play on this issue. I have both monitors side by side. I can move the cursor from one monitor to the other without a problem. Here is what is happening:
I move a Word File from...

Thanks Karl. Will try that and get back to you later

Windows 10, PC Dell Studio.
I have two Dell Monitors connected. They are connected as follows: One is VGA to VGA. The second is DVI to VGA. (I hope this is correct).
Both Monitors are showing in...