For a free piece of software, Windows Media Player is an excellent choice for managing your growing collection of video and audio files.
However to make the experience of using WMP complete you need to add a simple MPEG-2 Codec that will allow the software to playback your DVD collection too!
For more information on a suitable Windows Media Player DVD Plugin for your PC's operating system you can read Microsoft MVP - Marc Liron's article:Windows Media Player DVD Plugin
Please leave a comment if I can help!
Regards
Henry Davies Windows Media Player DVD Plugin Specialist