You are right about the connection, that was the problem, but I found a way around that so the issue is not the external dvd player now.
The issue is where to find the generic driver I deleted, which I am not sure of the exact name of the file, and despite a long search on the microsoft website it wasn't in any of the lists I checked. I deleted it as that was what was suggested to fix the dvd problem, but as it's plug and play, it was the wrong thing to do anyway as it could see a different external drive.
Obviously this driver file is not needed for what I am doing now, but I want to reinstall it, in case I need it in the future