Sounds like it is stuck installing an update. If you have time, let it do its thing. If it is stuck for more than a few hours, hold down your power button. When you turn the computer back on, you will likely have to wait for the update to be rolled back. If your computer is getting stuck installing updates, it is typically a good indication it is time for a reformat and reload the OS.
I have the same problem, and have had it for over a month. I've let it run for over six hours. I've reformatted my windows 8 operating system. And, despite being a novice at the whole computer game; I suspect that no one KNOWS the answer to this problem.