One of my friend’s just bought a Windows 8 laptop. However, when it was being setup for him at the store, he told the rep that he wanted Windows on C: and data on D:. On Lenovo laptops, the D: is used to store the default system recovery image and that too with hidden files. Therefore, any misadventure in moving the files over elsewhere, to make D: a data partition can result in lot of angst. To prevent this, make sure you first take a backup of the system. That way, even if you lose something, you can get back to where you started from.