Lucky for you there's an [[MacBook Folder With Question Mark|entire page on this exact issue|new_window=true]]. It's for MacBook, but the concept is largely the same.
As a former Geek I can say with confidence, Geek Squad would also still work on this if you decide to go down this route. Although it's usually a pretty straight forward. Bear in mind your options may be somewhat limited depending on what they find. If it's a hardware issue, that isn't something they can take care of in store.