after a long search, I found the microsoft update catalog site: http://catalog.update.microsoft.com/v7/site/Home.aspx
just search "Mirage" in the search box, and the proper Win7 drivers will appear.
I downloaded the latest driver, and it works with Extended desktop. ( Start button+p key combination )\
But, the 3D support of this drivers suck!
simple games like counter strike and Nba LIVE that worked great on the XP system, do not work well at all !
What do you think is the problem ?