Having read through it all I decided it would be easier to back-up emails if they were in My Documents so I went through the recommendations in the fifth post down.
When I went to My Documents I discovered 1. That while the seperate files in OE have been saved, I can't open them and I'm not sure if that's normal. The same applies to the addresses I saved.
But worse than that... 2. Some of the folders from OE and the emails in them have seem to have been saved to My Documents rather than just copied so I can no longer access them at all. These folders in OE, seven of them, are now empty.
I'm not sure how or why this has happened but can anyone tell me how to transfer the contents of these folders back to OE!