I was trying to clean up one of our servers the other day that was running low on memory. There was an old installation of Windows SharePoint Services 3.0 Beta on it (which included an instance of SQL Server Embedded). It wasn't being used, but the database process was using up memory and I wanted it gone.
Uninstalling was not so easy. The uninstall would fail within a minute. I then read somewhere that you needed to remove the SharePoint Language Packs first, so I tried that. That just made things worse. After the language packs were removed the SharePoint installer wouldn't run at all, saying it "The language of this installation package is not supported by your system." Now what?
Whenever I run into uninstall issues I turn to a shareware product called MyUninstaller. It gives you a little more control over the uninstall process than the Add/Remove programs does in XP. I'm not totally sure of everything it does, I just usually try it when my uninstalls fail thru traditional methods. In this case it showed 3 install packages for SharePoint and one of them actually worked (as far as I can tell).
Uninstalling SharePoint in this manner failed to uninstall the SQL Server instance. SQL Server was not listed in Add/Remove Programs but was listed in MyUninstaller. Unfortunately the embedded edition does not allow you to uninstall it. Some searching on Google brought me to this website that shows how to uninstall the embedded edition from the command line. You just need to get the uninstall string from the registry (or right from MyUninstaller) and append an argument. That worked.
It was a bit of a hassle to clear that software from the server, and I probably would have given up if I didn't know about MyUninstaller. Great app.