Hi @Joann Bolden,
Welcome to Microsoft Q&A forum.
I understand that you are encountering unexpected MSN popup windows while using Microsoft Word and Excel, alongside intermittent screen flickering that impacts your productivity. This behavior often stems from how the applications communicate with online services or manage background notifications during your session. It is frequently associated with specific configuration settings or the presence of active external extensions within the software environment.
To address this, I suggest you first disable the Start screen in your Office applications. Please navigate to File, select Options, and under the General tab, uncheck the option to show the Start screen when the application starts.
It is also helpful to review your active add ins by going to File, then Options, and selecting the Add ins category. Temporarily disabling these items can help determine if an extension is triggering the pop ups. Furthermore, please ensure your display drivers are updated through the Device Manager to stabilize the visual performance of your screen.
Please perform these steps and update me on the outcome. I am happy to provide further investigation if these adjustments do not fully resolve the situation.