I have a dropdown menu on my site through IFRAME that was working find for a while, but has suddenly stoped working. I can scroll through the options with the wheel on my mouse, but I can't get the dropdown list. It seems to work fine on other machines. What could cause this problem?  

Nedal:

If you are talking about the pull downs you have in your center content they are scrolling with my mouse.

You my have a browser copatability issue. Try clearing your cache/temporary internet files.

Try with a different browser.