Windows Media Player interacts with many system components, including hardware drivers, audio and video codecs, and DirectShow filters. It is possible that the Player is encountering problems because of a faulty or incompatible component from a software provider other than Microsoft.
In particular, we recommend that you use caution when installing codecs, such as some of the free codec packs available on the Internet that claim to include codecs from a wide variety of companies or organizations. Incompatibilities are known to exist with some of the components in these codec packs that can cause serious playback issues in Windows Media Player and other multimedia programs, lead to system corruption, and make it difficult for Microsoft Support to diagnose and troubleshoot playback issues.
For these reasons, we strongly discourage you from installing these types of codec packs, and recommend that you remove them if you have installed them and you are having problems with the Player. We recommend that you only install codecs, filters, or plug-ins from trusted, authorized sources, such as the website of the official supplier. Even then, we recommend that you use caution, because many codec suppliers offer minimal customer support.
We also recommend that you set a system restore point before installing any digital media components. This enables you to return to your original system configuration, if necessary. For more information about setting restore points, see What is System Restore?
For more information about codecs, see Codecs: frequently asked questions.