Can you find it running in the Windows 7 Task Manager? Press Ctrl+Shift+Esc to call up the Task Manager. On the '''Applications''' tab, any visible Firefox windows will be listed. You can select each window, use Switch To, then close the window (if the window is invisible, try Ctrl+w which is the "Close Tab" shortcut). Hopefully that will shut down Firefox. In that doesn't do it, click the '''Processes''' tab. Here you may need to click the "Image Name" heading to sort the list. Then look for firefox.exe. To "kill" or crash that process, you can right-click it and End Process. Hopefully this is rarely necessary. If you find that Firefox gets stuck in memory often, it may be hanging during shutdown, and we could explore why that might be happening.