Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Uninstall Office XP following the link below.
http://office.microsoft.com/en-ca/office-xp-resource-kit/removal-wizard-HA001136289.aspx
Try re-installing Office and check.
If you are not able to reinstall office, start the system in clean boot following the article below to check if any Non-Microsoft application is conflicting with Office and try installing Office.
Note: Read the disclaimer mentioned in the article.
http://support.microsoft.com/kb/929135
Note: Once the troubleshooting is done start the system back to normal mode following the 7<sup>th</sup> step in the article.
Ruchi Bisht