I'm assuming you don't see a Firefox window, so there's no obvious way to close it.

Have you ever used the Windows 11 Task Manager? You can call that up using Ctrl+Shift+Esc. Normally, it starts in an icon view; you can click the upper left button with 3 horizontal bars to show the icon labels.

Can you see any Firefox entries on the Processes list? If so, you should be able to right-click > End Task to terminate them. This does "crash" the process, so at the next startup, Firefox may do a crash recovery and restore your previous session.

If you do not see any Firefox entries on the Processes list, you can switch to the Details list and click "Name" at the top of the left column to sort alphabetically (if it's not in that order already). Scroll down and look for any firefox.exe entries. Again, you can End Task or End Process Tree to shut down that process.

If you don't see anything, hmm, there might be a lock file in your profile folder. More details on that if needed.

When i open firefox it comes up blank with the message below...and i can see it in the process'

See also:

• https://support.mozilla.org/en-US/kb/firefox-already-running-not-responding

Doesnt go to any link. cant use firefox then on this computer

Sorry, firefox got capitalized in the above link, this should work.

• https://support.mozilla.org/en-US/kb/firefox-already-running-not-responding