Did you recently have a trial version of Office 2007 on your computer and decided to uninstall it? Often, the uninstaller in the trial version of Office will break. This leaves Office 2007 permanently on your computer, in an unusable state. I had this happen to a client’s computer today and had to run some tools in order to get Office 2007 reinstalled.

When I tried to install Office 2007 “over” the trial edition, the installer would get a vague error saying “Office 2007 encountered an error during setup.” Read more for the solution.