Videophiles, gamers and audiophiles are all too familiar with codec conflicts. What many people don't realize, however, is that not only can these issues prevent you from viewing, hearing or working with a file, they can also seriously impact system operation or performance. Fortunately, there are several freeware and/or shareware utilities to help identify and resolve codec related issues...even if you don't realize you have any.
InstalledCodec InstalledCodec is the replacement for MMCompView and works on windows 2000, XP, 2003, and Vista. As with most similar codec utilities, the program runs as a stand-alone executable and doesn't need to install or add any DLL files to function. InstalledCodec allows you to enable/disable codecs, export the details of individual codecs selected or all installed, and will launch RegEdit and take you right to the actual registry value.
DirectShow Filter Manager DirectShow Filter Manager is another nice wrench to have in the toolbox when dealing with codec issues, and it's another that runs as a stand-alone executable. DSFM displays categorized lists of all codecs and filters, allows you to register/unregister them, provides complete details regarding the registry keys for each, and allows you to change the filter's merit (order of preference).
SHERLOCK - The Codec Detective SHERLOCK is an old school favorite that doesn't provide the ability to enable/disable codecs, but it does do a pretty decent job at identifying broken codecs; typically codecs that haven't completely uninstalled properly. SHERLOCK also provides the ability to export or print a text file listing of all the codecs installed on your system, providing basic information about each listing.
K-Lite Codec Tweak Tool If you're at all familiar with codec packs, you may be a bit leary about this one because of the name, but don't judge too quickly. This is a pretty handy little tool, as it has all the capabilities of previously mentioned tools and can automatically export a registry backup for you in the process. I'm not a big fan of the way they layed out the GUI, but other than that is has worked well for me on Windows 2000 and XP.
GSpot Last in my list, but certainly not least, is GSpot...everyone's favorite piece of software to have to refer to when testifying in court. This little gem is a must have for your bag of tricks when analyzing digital video files, and most are familiar with it for that alone. Did you know GSpot also allows you to view all of your codecs and filters installed, identify those that may be broken, see their detailed info, and even change their merit? *Clever GSpot name cliche goes here*
:: WARNING :: Editing your system registry can cause your system to become unstable or even completely innoperable. I strongly recommend that you backup your entire system or at the very least your registry prior to deleting or modifying registry values.