Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hello,
Thank you for your reply.
Let us try starting the computer in clean boot mode and then try to open Office application and verify the status.
Starting the computer in clean boot mode would disable all the non-Microsoft applications and the antivirus which could be one of the reasons for the error.
Refer the article below to start the computer in clean boot.
http://support.microsoft.com/kb/929135
Disclaimer: Ensure to restart the computer in normal mode after completing the troubleshooting steps.
I hope the above information helps. Let us know if you need further assistance.
Thank you.