Before I get into troubleshooting, I should address the nature of your license. An Office "Professional Plus" license is a volume license not authorized for distribution to individuals except through the home use program through employers. Such licenses are often sold by unscrupulous internet vendors. They will work when installed, but when Microsoft looks at the number and location of the installations in violation of the license agreement, they cancel the authorization.

I sincerely hope this is not your situation. If it is, your only recourse is through the vendor who sold you this void license.

Are you using the 32-bit or 64-bit version of Office. If the 32-bit version, consider switching to the 64-bit version.

Can you use the option to disable hardware graphics Acceleration? This needs to be done in PowerPoint or Excel since the option was removed from Word for some reason. It applies to all of Office, though.