"Drop downs" not working

Suddenly, within the last 2-3 days I have been unable to access the "Thread tools" and "Search this thread" popups/dropdowns from my usual browser, which is Firefox version 2.0.0.1. I tried IE and it works fine there, but I've not had this problem with Firefox before and it is all I ever use.

Just checked, same thing with "Forum tools" and "Search this forum" buttons at the forum level.

Thanks for the response. I was able to fix the problem, but can't recreate it now. I played around with security and java script settings with no effect. I refreshed pages, restarted Firefox, even rebooted without fixing the problem. Then, I was checking out the Tools/Add-ons menu and disabled the "Talkback" extension and that fixed it. Only problem is re-enabling it doesn't recreate the problem... Oh, well, at least it's working now. Thanks again.