On Tuesday I reported onfrom my Vista PC. I thought the problem might due to Outlook 2003 being installed on the same machine. When I upgraded to Office 2007, the older versions of the apps remained on my system, even though I never used them. This didn't appear to be a problem until Outlook 2007 took a hike.
My second surprise was my inability to uninstall Office 2003. Vista's Programs and Features Control Panel applet (which XP calls Add or Remove Programs) would pop up this error message: "This patch package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer patch package." You'll find more information about this and similar Windows error messages in this Microsoft knowledgebase article.
The fix entails downloading and running Microsoft's Windows Installer CleanUp Utility (this link starts the download automatically). The program also helps cure problems you encounter when trying to install Office and other apps that rely on the Windows Installer, including Adobe Acrobat. After you download and install the program, open it by clicking its shortcut on the Start menu, select the app from the list, and click Remove > OK > Exit.
Pay attention to Microsoft's warnings about this tool: It changes your Registry, an activity that's always fraught with peril. Also, if you reinstall the program, make sure you use the same directory as the previous installation to avoid placing duplicate copies of files on your hard drive.
I'm happy to report that Outlook 2007 has remained in place since I removed my old Office apps using the installer cleanup tool. I can't say for sure that the two problems are related, but a fix is a fix.
Monday: Clear space on your hard drive by manually deleting the unnecessary files that auto-cleanup tools leave behind.