Nokia (NYSE:NOK) has entered into a contract with Microsoft (NASDAQ:MSFT) to provide the Windows Phone OS for its Lumia phones, but in this video, Motley Fool tech and telecom analyst Andrew Tonner discusses why Microsoft may also be a potential threat to Nokia a short way down the road. He tells investors about the possibility that Microsoft is working on its own phone, the Surface Phone, which could eat into Lumia sales. Andrew tells us what this could mean for Nokia, and what it tells us about Microsoft's drive to have the Windows Phone OS succeed.