Unable to Log into iCloud from PC

I am trying to use the Find My iPhone feature of the iCloud. I have successfully enabled it on both my iPad and iPhone and I'm able to view them from each of my devices. When I go to a PC and log in to: https://www.icloud.com, it asks for my Apple ID and password. I have entered my ID and password a dozen times, changed my password, opened an @me.com email upon several other trouble shooting attempts and I cannot log in to the iCloud site. It tells me my Apple ID and password is incorrect. - Mind you I had to log into the Apple site to submit this discussion so I know my password is correct. Why can't I get in to iCloud to view my devices?