Shaen,
Try this:
1. Launch the PowerPoint application.
2. Go to File > Options> Add-ins.
3. Go to Manage > select COM Add-in.
4. The ESRI maps for Office > Go. Check on the add-in for ESRI .
5. In the Manage option > Disabled Items > Go. Enable the ESRI add-in add-in.
Does the ribbon now appear in PowerPoint? Please advise.
Regards,
Robert LeClair
Esri-Denver