I do not know when or how it had happened, but sometime after updating to Windows 8.1, I found that I was unable to open Word, Excel, PowerPoint or any Office documents. It looked like my Microsoft Office 2013 installation had become corrupt.
I tried to uninstall Office 2013/2016 through the Control Panel > Programs and Features > Uninstall applet. But it did not work. Right-clicking, selecting Change and trying to repair Office also did not work.
Then I came across this Microsoft Fix it that let you easily remove or completely uninstall Office 365 or Office 2016/2013 suites and programs.
Uninstall Microsoft Office
Download the Microsoft Fix It, exit all Microsoft Office programs and run the Fix It.
It will ask if you’d like to Apply the fix or Skip the fix and continue troubleshooting. To uninstall Office, I selected Apply this fix.
The uninstaller will run for a minute or two.
After a few minutes, the troubleshooter would have completely uninstalled Microsoft Office from your computer.
If you selected the Troubleshoot option earlier, you will be notified of problems found, if any.
Clicking on View detailed information will give you some more information about the problems.
Have a look at Office Configuration Analyzer Tool. It will help you analyze & identify Office program problems.