If you are running into Office activation issues, and would like a quick solution, please check the following links to help you resolve the problem:
-Office 2010: Check this step-by-step Online Solution Wizard.
-Office 2003 or 2007: Check this link:http://support.microsoft.com/kb/2549291
|Online Solution Wizard
A step-by-step solution is available to resolve this problem.
If you need to reinstall Office and lost your media, you can install it online. Check this link for instructions