I recently reinstalled my Windows XP Pro and then SP 2, basically a complete reinstall and had the exact same problem viewing DVDs, the decoder couldn't be found. I found reinstalling Windows Media Player from the Microsoft download site corrected the problem. First uninstall the Windows Media Player from Window Control Panel's 'Add and Remove' (and then clean the registry if you have a registry cleaner), then reinstall Windows Media Player from MS's download site. Everything worked just fine for me after doing this. Yeah it is a hastle when things don't work. Try that though and let me know if it works. You shouldn't have to run out and buy anything new. Window's Media Player is free. Get their # 10 current Player.
PS I also lost a WinDVD Player in the process. I went to Win's site and couldn't find anything free so I downloaded their trial version for 15 days free use, something like that. Anyhow, I usually just use Windows Media player anyhow. Seems to be quit enough.
PPS If you already haven't figured this out.
Edited by Johnz414, 25 April 2005 - 09:10 PM.