The Windows installers for Blender don't cleanly upgrade older versions. They blat over the files in the main Blender folder and the Start menu, but don't remove the version-specific subfolders. They also don't remove the old Add/Remove Programs entries, and since those don't include any version number data the user ends up with multiple duplicate entries.
The Windows installers should check for older versions and perform a clean upgrade (possibly by simply running the old uninstaller first.) This would bring Blender inline with other software packages. Also, the version number data should be added to the Add/Remove Programs entry (and maybe "publisher" could be set to "Blender Foundation" etc. at the same time :-)
Tested upgrading Blender x64 2.54 Beta to 2.55 Beta, on Windows 7 Ultimate x64.
Description
Description
Event Timeline
Comment Actions
No they don't, because that's not implemented.
To remove you should use the uninstaller of the previous version. Currently I'm contemplating to even not have an installer at all, but at most a self-extracting archive and some .bat files to register blender.exe and maybe add some links.
Moving to todo for further contemplation and work: http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Install-OS#Installation