ExtendSim was uninstalled, but the folders are still there.
When ExtendSim is installed, two ExtendSim folders are created. By default one folder is placed in Program Files and the other is placed in Documents. There are two reasons why one or both of those folders are left after you uninstall ExtendSim:
The installer can't uninstall files it didn't install. After installation, ExtendSim creates various files (ExtendSimDocPath.txt, a license file, etc.) Also, you may have created models and libraries and saved them to the ExtendSim folder. When ExtendSim is uninstalled, only the files that were originally installed get deleted.
The installer doesn't know if an ExtendSim folder has been moved after installation. For example, it cannot remove any of the files in an ExtendSim folder that was moved from the Admin's Documents folder to the end-user's Documents folder.