Microsoft Word is creating problems. Sometimes it runs and sometimes not.
When the files crash then these problems appear.
You have not to worry about. Do as I say.
Click on help on menu bar, choose detect and repair from the drop down list.
It will check all the files and will repair if found any damage file or corrupt registry string.
It will take some time.
After this process, it is better to restart your computer.
Then check the word. The problem will be 100% solved.