Error message every time I start Firefox
Message is "Firefox is already running, but is not responding. The old Firefox must be closed to open a new window." I uninstalled/reinstalled several times with the same result.
Opaite Mbohovái (2)
What is your computer system and Firefox?
Do you have the Firefox icon on your quick launch? Close Firefox. Right click on the icon and select Open New Tab. Sometimes this works. If it opens, close it by Menu > File > Exit.
This is not a cure but will make it easier if Firefox locks up in Windows. https://support.mozilla.org/questions/997866 {web link}
https://support.mozilla.org/en-US/kb/websites-look-wrong-or-appear-differently
https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster
https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix
https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding