Are you looking for a free DVD player software for your computer. Well I have tried most of them, and the only one that has worked for me so far is AVS DVD Player. It has been able to play my commercial DVDs without any problem.
Most new computer that are equipped with a DVD player installed, generally come with a limited version of CyberLink PowerDVD or InterVideo WinDVD. You can also use Windows Media Player, but it requires you to install a 3rd party MPEG2 codec to view the disks.
AVS DVD Player supports the following formats: regular DVD (PAL, NTSC, VCD, SVCD), MPEG4 (including DivX, XviD, etc.), MPEG1, MPEG2, AVI, Real Media video, Quick Time files, WMV files (including WMV-HD), H.263, H.264, mobile video formats (3GP, 3GP2, MP4).
The software is not perfect, it has its flaws (and bugs), but overall it works. My biggest complaint it that it takes a long time to start a DVD.