MCI error running Windows system other than XP SP1
If you are running versions of Windows other than the version of XP that Comes pre-installed with SP1, and you get errors such as "MCI error - Unknown video format" or some other message i.e. Media Not Open, then this can be caused by a variety of problems.
You need to try the following:
Make sure you are using the latest version of the video drivers for your graphics card - see the manufacturer's web site. You should also do the same for your sound card drivers.
Try installing the latest DirectX from:
http://www.microsoft.com/windows/directx
Try installing the latest Windows Media Player from:
http://www.microsoft.com/windows/mediaplayer
Try uninstalling any third-party DVD players, as these have been known to mess up MPEG1 replay. If uninstalling the DVD player fixes the problem, then contact the supplier of the player software for an update.
Certain video editing software, such as some products by Pinnacle, have also been known to cause problems. If so, contact the supplier.