When trying to troubleshoot Microsoft Word startup problems, it can be very
helpful to utilize the command line switches at startup.
Start
Run
"C:\Program Files\Microsoft Office\Office\Winword.exe" /a
/a - prevents add-ins from loading and prevents global templates from loading
/m - prevents any autoexec macros from executing
/s - safemode
/r - re-registers Word
Source and more switches: Microsoft Support KB210565