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.”

The fix:

The following instructions are at your own risk. We take no responsibility if it leaves your computer is a damaged state.

1. Manually uninstall as many components of Office 2007 as possible:
http://support.microsoft.com/kb/928218/

2. To forcefully uninstall a program on your computer, download the Windows Installer CleanUp Utility at:

http://support.microsoft.com/kb/290301

Once installed, it should appear in the “All programs” section of the Start Menu. Run the program. Remove all instances of Office 2007 (trial, student and home edition, etc.) Reboot the machine. Run the installer for the  full version of the Office 2007 product you purchased. It should now install.