Barnes & Noble has asked the government to investigate Microsoft, saying that the software giant is unfairly trying to corner the mobile market. A lot is riding on the big leather chair-studded bookstore's new Nook Tablet. Possibly the survival of the business itself. So it doesn't want to spend a ton of money on the lawsuits that could be seen as inevitable coming from Microsoft. Microsoft has made a habit of going after any device manufacturer that makes something using the Android operating system, which Nook Tablet uses. Microsoft maintains that several features of Android use patents that Microsoft owns. Rather than fight Microsoft on those claims, companies like Samsung and HTC just settle and pay Microsoft a small percentage per unit sold. B & N would rather not.