Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies do the following:

1. Go to Firefox > History > Clear recent history or (if no Firefox button is shown) go to Tools > Clear recent history.
2. Under "Time range to clear", select "Everything".
3. Now, click the arrow next to Details to toggle the Details list active.
4. From the details list, check Cache and Cookies and uncheck everything else.
5. Now click the Clear now button.

Further information can be found in the Clear your cache, history and other personal information in Firefox article.

Did this fix your problems? Please report back to us!

that fixed it> thank you.

This happened today Feb. 20, 2013, but I tried your solution, it did Not work. Please advise, I go to internet explorer, it looks normal yahoo home page, but is totally bogus looking in mozilla ( yep latest version) firefox. I am so annoyed and frustrated, have tried all i can think of... and tried yours, but no luck at all.

I have exactly the same issue. IE V8 works fine. Firefox V19 works fine on my Win 7 64 bit pc. This issue is on my Win XP Home SP3 pc and is driving me crazy.

This occurred after my updating to Firefox 19.

Please give this attention and give us a solution.