Launching Microsoft Office Setup
Fire up Control Panel, and in Add/Remove Programs or Programs and Features (depending on your version of Windows), you’ll find Microsoft Office listed:
Right-click the Microsoft Office entry and click Change:
That will start the Microsoft Office Setup program.
Repair with Office Setup
You will likely need your original Microsoft Office installation media – either the original install CDs, DVD, or the equivalent.
Microsoft Office Setup starts with a choice of what action to take:
Make sure that Repair is selected and click Continue.
This can take some time as Office Setup validates and repairs your installation.
Eventually the repair completes:
Click Close and you may be faced with this:
Microsoft Office’s repair may require that you reboot your machine for the changes made to take affect.