Sorry FG, only saw this thread now

Depending on what type of dvd movie and the software he actually used, there should be no real reason for the DVD not to work... it should work in any DVD player - even stand alone players.

As curio pointed out, the extensions are all the same (as they should be), however, you simply can not view the files from explorer, as with any DVD.... There may have been an option in the software that enables CSS encryption or the like, so your best bet would try to extract the DVD contents using DVD decrypter and then using PowerDVD to view it.

What exactly did he use to burn the DVD and what do you want to do with the files?