Well....

Last I checked, Microsoft Windows Vista is not open source. Meaning that the source code for the chess game included with the operating system will not be released to the public.

But, there is hope, if you would like a chess program using C#, then that isn't too tough. There are many open source chess games using C#. Like this one here. If you would like your game to be exactly like the game in Vista. Then I would suggest taking a game like this and modify the code. It will be tough to get it to look and act exactly the same, but I bet you can get pretty close.