Mozilla Firefox Problems

Hi,
I have been using Firefox for years and never had any problems. Now all of a sudden the back and forward arrows on the browser have begun to stop working. I can still see the arrows, but they're faded and grey like when you're not allowed to click something on your computer. Most of the time they work, but the times that they don't are becoming more frequent and it's extremely irritating. The arrows will be fine all day until all of a sudden they're not. Today the same thing happened only it was the options that I couldn't click; file, edit, etc. I couldn't click anything. I've tried messing with the settings but it doesn't help. I'm so frustrated.


Help please...