Word does not maximize to full screen
Solution 1:
I've seen this before. I had a system where I was messing around with the resolution and Word "remembered" the current resolution incorrectly. I don't remember exactly what I did to fix it, but I believe I just changed the resolution, opened/maximized/closed Word, then change the resolution back to your preferred setting, and then do the same.
Solution 2:
I got the same problem, What you should do is go to Windows Task manager / Processes, select WINWORD.exe and End Process, restart the Word and it should open normally.