A couple of days ago I tried to uninstall Telerik's r.a.d.controls 2006 SP3, and the uninstall ran forever before finally failing with an error code. I logged a support ticket and was told that the uninstaller wasn't yet compatible with Vista, but was given a workaround that you might want to know about...

Apparently there is a Microsoft Utility called the Windows Installer Cleanup Utility. You can download it here. It doesn't uninstall programs, but it cleans up their footprint in the installer database and registry. You can then delete the installed files manually and the offending software at least looks like it's gone. Of course, using this brute force method, some things don't get uninstalled, but at least it cleans up somewhat.

If you use this utility, run it before you delete the physical files. It seems that you cant do it the other way round.