Have you tried your same PC/browser but going through a proxy? Have you tried your same account on the same PC in a different browser? Tried logging in from a free/unsecured wifi somewhere? Tried deleting cookies in your browser? Tried a different PC (library, friend, other family member, etc.).
Perhaps it's just my mood this AM, but it seems rather "do my homework for me" of you to post this up without having done some research and troubleshooting on your own.