The message from the GSX installer you posted in your first post told you exactly that: how to find the SODE uninstaller.
In the "Program and Features" section of Windows Control Panel, named "Simobjects Display Engine".
"Program and Features" changes its name depending on the Windows version and the language but, it's the same place were every Uninstaller of every Windows program out there is normally located.
The question is: what you do if for some reason the uninstaller doesn't work (usually because you removed the program *by hand*, big mistake...) or it's not there ? In that case, to fix the uninstaller, you must find the *original* INSTALLER, so you can repair your installation including the uninstaller, which will surely work then.