OK, I did have the Remember Credentials box ticked but it kept asking for details each time. I disconnected the drive in Safe Mode as you mentioned and used Option 2 to create a folder. This time it worked. It shows up in Explorer as a folder and does not have any red X beside it. When I left click the mouse on it, the Remember Credentials message appears after a few seconds. I enter my details and it connects.
Thanks for the help. I will post back if any more issues....