I would recommend searching for any residual files from your previous version of Office.
1) Uninstall Office 2010
2)- Use the Windows Installer Cleanup Utility to clear any traces of old Office versions (XP, 2000 and 2003).
http://support.microsoft.com/kb/290301- For Office 2007, mydigitallife.info created a great app that clean Office 2007 for you:
http://depositfiles.com/files/nvvrvjwpm3) Now you should have a totally Office free Windows OS.
4) Reinstall Office 2010 and keep us posted!
Cheers!