Hello If you are trying to reinstall Open your browser and go to [https://www.firefox.com/en-US/ mozilla.org/firefox] Download the installer and run it. '''Once it finishes''', it should ask if you want to make Firefox your default browser. Select '''Yes'''. If you have reinstalled it but it still opens in Windows edge, right-click the Firefox icon on your desktop, select '''Properties''' and look at the '''Target ''' box. It should end in \firefox.exe. If it says something about msedge.exe, delete that shortcut and create a new one from the C:\Program Files\Mozilla Firefox folder. or go to installation folder eg C:\Program Files\Mozilla Firefox right-click '''firefox.exe''' and select '''Send to Desktop (create shortcut)'''. Are you seeing any specific error messages when you try to run the installer, or does it seem to finish normally?