Warning: ATI Catalyst driversFriday - January 20On various forums people have reported major video playback problems. Parts of the DirectShow subsystem of DirectX are broken. We suspect that this might be the result of upgrading the ATI drivers. There is either a bug in the installation of the new 6.1 version of the ATI Catalyst video drivers or something might go wrong during the removal of the old driver (perhaps an overly aggressive driver cleaner tool).
Steps you can take to try to fix the problems:* Start > Run > regsvr32 devenum.dll
* Start > Run > regsvr32 quartz.dll
* Re-install
DirectX* Install older ATI driver
Source:
K-Lite Codec Resource Site