I have always liked Microsoft's mice the best, so I always try to keep up with the latest version of IntelliPoint.

My current favorite mouse is the Wireless Laser Mouse 8000, which connects via a small bluetooth dongle, is as smooth as glass, and is fantastically accurate.  The only grudge I have is the location of the "forward" button (which is not even set to "forward" by default) — it was moved to the right side of the mouse, rather than staying under my thumb together with the "Back" button.

Microsoft recently upgraded IntelliPoint to version 6.2.  When I went to install it, it would almost finish, and then I'd get a nasty error box, which naturally was completely unhelpful, telling me that the problem could be disk space or "some other problem".  Nice.

I even tried uninstalling the old 6.1 version, but it refused to uninstall.  Arg!

Googling, I found a utility called "Windows Installer CleanUp Utility".  Sometimes weird install bugs are caused by a new versions of Microsoft installer software, so I gave it a try.

I installed and ran the application, the selected the IntelliPoint 6.1 software and clicked "Remove".  A peek at Vista's "Programs and Features" Control Panel applet confirmed that the software was removed from the list of installed programs.  ("Programs and Features" is the same thing as XP's "Add or Remove Programs".)

Then I tried installing 6.2 again, and it worked fine and completed normally.

The nice thing about the Windows Installer CleanUp Utility is that it is a real program that is now on my PC, ready to use if another install gets screwed up.  Thus, I would definitely recommend it to others as an important toolbox item.

Just a word of caution though: it should really only be used after all other options have been exhausted, because it permanently removes software from the list of installed programs.

Here is a link to the utility info and download page:

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