Firefox (3.6.8) works when I first start it. After a while, (could be anywhere between 5 minutes to 2 hours) it won't load any more web pages. I can press the back button and it can go back to the last page, but it won't go forward again. After waiting for the pages to load for over an hour, it still does nothing so I close Firefox. I try to start it up again but it says "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system." I have to close it out in Task Manager each time it hangs like this. This happens almost every time I use Firefox.