Microsoft (MSFT) is sliding significantly after the company announced that the head of its Windows unit, Steven Sinofsky, had resigned. However, in a note to investors earlier today, Stifel Nicolaus analyst Brad Reback suggested that Sinofsky's resignation could help Microsoft over the long term. Reback wrote that he had heard that Sinofsky "had a very polarizing personality" and difficulty "effectively working across groups." As a result, Reback thinks that Sinofsky's departure could result in increased collaboration across groups at Microsoft, and make the company more competitive in its battles against Apple (AAPL) and Google (GOOG). On the other hand, Sinofsy's departure will hurt Microsoft in some ways, since he was able to launch software updates on time, and helped the company overcome the problems created by its Vista product, added Reback. The analyst maintained a $36 target and Buy rating on Microsoft shares. In mid-morning trading, Microsoft fell 92c, or 3.29%, to $27.07.