From the KnowledgeBase
Vista: Why can't I play DVD movies on my computer anymore?
If you have upgraded your Windows computer to Vista Business or Vista Enterprise, and your machine originally shipped with Windows XP, you may receive the following error when you insert a DVD movie and try to play it:
"Windows Media Player cannot play the DVD because a compatible DVD decoder is not installed on your computer"
Unfortunately Vista Business and Vista Enterprise editions do not include DVD decoders and cannot play DVDs (although Vista Ultimate does, and can play DVDs).
To resolve this issue, you will need to purchase a Vista-compatible DVD decoder. The recommended DVD decoder is Cyberlink PowerDVD. Once PowerDVD is installed, you can use it or Windows Media Player to play DVD movies.
- Faculty and staff for institutional purchases only can buy Cyberlink at the PSR Web Store.
- Faculty, staff, and students who wish to purchase Cyberlink PowerDVD for personal purchases can go to www.dell.com/princeton.
Note that future DeSC and FCP Windows Vista Enterprise machines will include this software. In addition, Dell will include a license to the Vista version of this software on machines that ship with Vista Home Basic or Business installed. This solution only applies if you have upgraded your computer to Vista Business from Windows XP.