Please, in this case try the following steps:
1. Update your video drivers, and/or try different video hardware.
2. Disable Hardware rendering. As a quick test, you can use the DisableHWAcceleration registry value discussed here. You would set the value to 1 in order to disable WPF's hardware rendering pipeline. Note that this affects all WPF applications running in that user's session, so be advised you might be impacting more than one application.
3. Upgrade to the latest version and service pack level of the .Net Framework available for your target platform.
Or there is the easiest way to disable Hardware rendering in Office without use Registry Editor.
How to disable Hardware rendering in Office:
Open any Office component and create a blank document, click FILE.
Next, click Options in the following screen:
Moving on, in the below shown window, select Advanced in the left pane. Then in the right pane, scroll down and look Disable hardware graphics acceleration under the section Display. Check this option and click OK.