I use Ccleaner after surfing the web and every time I start to clean th disk I am asked to close Firefox in order for Ccleaner to clean the cache. This has been happening for some time now and although I invoke task manager it doesnt show firefox as running but when I use Process explorer I find it and have to kill the process in order to clean the computer. When I try to open firefox I am told that firefox is already running and that I must open a new window but the browser has been closed. However it is still running as a process. Why doesnt firefox close completely?