Here is a video demo of the new “Windows Phone 8” start screen on Lumia 900 running on WP7.8. As informed earlier WP7.8 will be the update for old Lumia devices which will bring elements like “start screen” and “various tiles size” from WP8 to these devices.

Check the video from  below,

[youtube=http://www.youtube.com/watch?feature=player_detailpage&v=ekjJ0w6CXew]