No, unfortunately. There is no free DVD codec for PC use. Your trial version or PDVD will operate for five minutes, then stop playback. Alternatively, there's a well-hidden Microsoft page that will allow you to upgrade Windows Media Player to play DVDs. It was $15 last time I checked, and not too many additional features.
Here's the link:
http://www.microsoft.com/windows/win.../buypacks.aspx
For some reason, you may get an error page when trying to reach this URL. Just reload and it should come up.