Nero Showtime Problem

Apologies if this has been answered elsewhere, I’ve searched the forums and not found the solution.

I am having trouble getting Showtime to play DVDs.

I also have PowerDVD installed and that works perfectly. Showtime will play audio tracks but when I insert a pre-recorded DVD it reads the drive and apparently finds no movie tracks on the disk.

I got Nero with my Plextor, so it is an OEM version. I have updated it to the latest version from the Nero site and had no error messages or anything to say the OEM licence doesn’t include Showtime.

Can anybody offer any ideas please?