Edge is a new browser only found with Windows 10. If you would like to get back to IE you can do so by first navigating to any webpage by entering in an address into the URL Address bar. Then select the top menu button (Upper Right). Last elect Open with Internet Explorer (IE). This will open the IE browser and RoboForm should already be attached.
You can utilize the image below to find the key points for 1. URL address bar 2. Menu button 3. Open with IE option.