Hey .. please read the article....i hope you will find the solution easily : [[Firefox won't start - find solutions]] thank you

What error messages do you see ? Can you attach a screenshot ? *https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem *use a compressed image type like PNG or JPG to save the screenshot ---- If you get a "Windows cannot find.." alert then this is a problem with Avast making changes to some registry keys. *https://answers.microsoft.com/en-us/msoffice/forum/all/windows-cannot-find-cprogram-filesmicrosoft/963fdedb-71d9-4f2e-b8c2-561b8767b012 *HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options => Debugger See also: [/questions/1290490] Windows Cannot Find Firefox.exe # Open: run (Windows key + r) # Type: regedit # Navigate/Search to Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Option # Delete the (Debugger) folders of apps that do not work