This problem comes when you installed your OS using a USB stick or Directly from hard drive and trying to install MS Office in your PC.
Actually, while installing MS Office on the pc, it shows "The windows installer service cannot update one or more protected windows files. Rolling Back Changes..."
You can fix it by putting a dll file fp4autl.dll (Download From Here) in the directory
"c:\program files\common files\microsoft shared\web server extensions\40\bin"


Simply download the dll file FROM HERE and put in the place i told above and install your ms office. You will see it's installed easily.