Will the Nokia-Microsoft alliance slow down Androids pace?

As part of a new agreement, Nokia will adopt Windows Phone as its choice smartphone platform, and Bing will become the default search engine on all of Nokia’s phones! This is the hottest news in the tech industry. This is a bold move by Nokia which is still the market leader in mobile hardware but being outclassed by Android and iPhone in the smartphone arena. Samsung on the other hand is working hand in hand with Google to sit on top of the Androidmarket.
The question is why Nokia chose to go for Windows over Android?  I think there could be several answers to this question.  The one that comes first to the mind is the enemy of my enemy is my friend. Nokia’s growth is falling in hardware sales and Windows is finding it difficult to maintain its market share.  This gets more interesting with Apple’s obstructive strategy towards supporting other OS or Apps. HTC is on a speed boat too and trying to tackle Samsung! Blackberry however is getting squeezed like

never before and is taking its last breaths with the help of BB services.
Coming back to the question, what can Nokia do with Windows which it wasn’t able to achieve with the Symbian OS? What other rational options did Nokia have and what flaws do you see with respect to its current alliance with Microsoft? Did it just happen cuz the current CEO of Nokia has previously led Microsoft and getting both managements strategically aligned was easier? If Nokia and Windows succeed to outclass Android, will the entire hardware vendor market fall which are surviving on Android OS products? Please share.