Backed into a corner, I'm needing to install SQL Server 2005 Express on my home computer. Like so many of us, I installed a few MS beta products during '05 and '06 while trying to keep abreast of changes to the tools of my Trade.
Unfortunately, the installer for the final version of SQL Server 2005 Eggs-press won't uninstall conflicting pre-releases of itself -- it simply complains and exits.
Of course, many of the pre-releases won't uninstall, complaining of various problems. My problem was that the ".NET Framework 2.0 is not installed." Bullshit!
After six different installer repairs and reboots (sigh), I ran across this tool buried in the Microsoft website:
It uninstalls all pre-release versions of the .NET Framework (2.0 and 3.0), SQL Server Express (and related), Visual Studio 2005, and MSDN libraries.
I found it here, on Aaron Stebner's WebLog, where a warning is given that it mistakenly also uninstalls the final versions of SQL Server 2005 Express. Hey it's all good, so long as it lets me finally install the working version!
Anyways, I hope this helps out somebody else.