Reinstall Office 2011 on my Mac with my already paid license

I must have made a mistake and moved Microsoft 2011 folders because every time I try to open Excel or Word... I get the "Microsoft Error Reporting" window and the application closes. I bought my license in 2011 and I haven't updated since. On my iMac, I don't have a guest account and my model is 21.5 inches mid-2011.
I've searched on blogs, and it is recommended to uninstall Microsoft and reinstall Office for Mac 2011; I have the key on the back of the CD.
For your information, I'm not a computer expert.
Thank you in advance for your help.

The uninstallation/reinstallation of applications is more of a Windows reflex; on a Mac, it's usually pointless. You don't specify the update level of your version of Office (a right-click on the icon of one of the applications in the /Applications/Microsoft Office 2011 folder will allow you to "Get Info"), nor the version of macOS running on your Mac (check via the "Apple" menu > "About This Mac").

You can easily create an account or allow guest login in the "Users & Groups" system preferences panel. This is a useful test, as it helps determine where to look for the source of the problem encountered (most often, it's in the settings and configurations of the usual user account).

If you really want to reinstall the applications (but to me, that's very premature and likely unnecessary), do so by following the instructions on this page.

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Hello at home!
Bernard

The office version was created on 03/10/2011 and noted modified on 08/15/2016 version 14.6.6
The macOS version is 10.12.6

Hello,
I created the guest account last night, I also tried to launch the installation package but I couldn't.
I finalized the account creation and launched Microsoft, and I got the same error message.
So I proceeded with the installation of the package which went smoothly this morning.
I relaunched Microsoft immediately after and it works!!
I am super happy because you seemed to write that a update was needed but that it wouldn't help.
So I wanted to say a big thank you for your help!!
I wish you an excellent day.
Loulou