I have a nasty feelng that this is going to turn out to be a "Doh" moment, but at the moment I don't see it.

As 'catters may recall between Xmas and the new year I had to rebuild ALL my computers. Even the one that had the least done was treated to a reshuffle of hard drives and optical drives. 3 computers, 6 optical drives. A DVD drive or better and a CD-writer or better in each computer.

I rarely play DVD movies on the computers. Today, it pans out, although ALL the optical drives will read CD data discs, and all will read and play CD audio discs, only one will read and play a DVD, and that one does so without sound. OK the CD-only drives won't read a DVD anyway, but this is starting to look like installer error.

What am I missing?