Nokia’s (NOK) switch to Windows Phone hasn’t gone as swimmingly as some industry watchers predicted. While investors finally saw an upside last month, Nokia recently reported its third consecutive quarter in which the struggling smartphone vendor lost at least $1 billion. Nokia is staying the course, however, and it remains Microsoft’s (MSFT) best chance at busting back into the smartphone market. As picked up by Chinese blog WPDang, aÂ Weibo user on Tuesday posted two images of a prototype Nokia Lumia phone running what appears to be Microsoft’s next-generation Windows Phone 8 operating system. The phone could also be running Windows Phone 7.8, the less significant update Microsoft will make available for existing Windows Phones, and the Weibo user has since deleted the images from his account. Smartphones powered by Microsoft’s Windows Phone 8 platform will reportedly begin launching in November.