I have a mac running OSX 10.6.8 and I'm having issues with firefox not responding so then I close it. Then when i try to open firefox it says "A copy of Firefox is already open. Only one copy of Firefox can be open at a time." I look in the activity monitor and it does not show that firefox is running. The only solution i have found is to completely restart my mac, which is not convenient to do often. I have searched elsewhere online for a solution, but i could not find one. Any help would be appreciated. Thanks