White Box when Trying to Login to icloud.com

I have been trying to login to icloud.com from my PC for some time now. I have never had a problem before. Now, after typing in my id and password, it gives me a white, blank box. After about 30 seconds, the white box goes back to the login screen. When I try it again, it does the same thing. My PC...windows, firefox, everything is updated and meets the requirements listed. When I tried to get on from Google Chrome instead of firefox, it took my id/password but then asked me security questions that I never picked or answered. I know this because I did not even know the answers to them! I never would have picked them. When I went to the site to change my security questions, I cannot even get to that because when I try to type in the id/password...I get the darn white box!! Please help.