Start at step #2 #close Firefox with File > Exit or "Firefox" button > Exit. Give Firefox some time to close and #'''check that it finished via Windows 7 shortcut to WTM "Ctrl+Shift+Esc" in the "Processes" tab''' to make sure that firefox.exe is no longer running -- if it is still running then terminate it by selecting the use "End Process" button or from context menu. #proceed with the install