hear hear...

Big words for someone that (so far) wasn't able to provide any help himself, and the Problem described a mere 11 hours ago.

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Anyway...

If the System can't do something as basic as render a Video File despite all Codecs being installed, the Problem is often buried deeper in the System.

First of all, I'd make sure a default (reference) Driver is installed for a safe Start.
Then, make sure no other Application (can be a background Task or alike) is using the Primary Overlay surface (if it is already in use, there should be an error Message, but you never know).

Try to play a generic .mpg (MPEG1 or 2) File, this should work any day with any Card, since it's using old Windows default Codecs.

If even that doesn't work, the Problem might not be the Video Card after all, but rather an error somewhere in the System.

I've often heard people solving similar (minor) Problems with their Video Hardware by switching the DirectX Video Hardware Acceleration slider back one or two nothes.

Sometimes it helps to install one of the available Codec Packs, as it will correctly re-register all selected Codecs to the System during Installation.
( http://www.free-codecs.com/ )