Last month M$ released the new G4WL dashboard which was windows friendly instead of console display.
And worked in game only something that was supposed to be fixed to a desktop application.
and Marketplace was mia from the release as well.
Anyhow M$ slipped in the new update quietly still under GFWL redist 2.0.
Here is the link https://www.microsoft.com/downloads/details.aspx?FamilyID=6f966188-1e50-41c3-a689-181edc57c0e0&DisplayLang=en
This installer has the Desktop application so you no longer have to access the dashboard when in game it can be done on your desktop Marketplace is included.
It shows all Xbox360 games as well as your GFWL games.
There is not much in the marketplace for PC except the Viva Pinata Demo.
M$ plans on adding downloadable content and Movies and full game releases.
And of course the new GFWL is no longer a pay service it is free on the PC. Xbox 360 still requires a gold account for full access to online games and newly released demos.