If you’re having problems opening your Microsoft Office documents or spreadsheets, or emailing such files, a Microsoft Update is the likely culprit. Other symptoms of the bad update include your document icons may change to orange, and trying to open them gives a prompt to install, purchase or activate Microsoft Office.
To fix the problem go to the Control Panel > Programs and Features > right-click on Microsoft Office Starter 2010- English and click “Change”. This will Repair Microsoft Office and should fix the problem.
See this Microsoft TechNet article about the problem if you are still having problems after the repair, or want to learn more.