I usually get this error-prompt box every time

I usually get this error-prompt box every time

Hello Victor.

This sort of problem is apparently caused by problems in the system registry.  The fix for this problem is actually rather lengthy so I will post this link from Microsoft Support site:

https://support.microsoft.com/en-us/help/921541/how-to-troubleshoot-problems-that-occur-when-you-start-or-use-word

There is actually an automated fix via Microsoft Fix It but you can also opt to do it manually by deleting the following registry keys.

HKEY_CURRENT_USERSoftwareMicrosoft Office10.0WordData

HKEY_CURRENT_USERSoftwareMicrosoft Office10.0WordOptions

The "10.0" is for Office 2002 only.  For Office 2003, 2007 and 2010, replace it with "11.0", "12.0" and "14.0" respectively.

However, the fix is very complex so I urge you to use caution and backup the registry prior to following the procedures.

Hope this helps!