Wierd DVD issue



Hi all. I have an external HP DVD Writer 840e. I can read and write CD’s just fine, be it music or data CD’s. I can also write DVD’s…movies or data. The problem is, for some reason, I cannot read a commerical DVD. I can read a data DVD fine and a burned movie on a DVD/R just fine too, but I can’t read a commerical DVD. It doesn’t even show up as having a disc inserted in the drive. I have the latest firmware installed. I also have the region code set to 1. My DVDs are all US dvd’s.

Anyone have suggestions?