Attempting to login to most websites results in login page refreshing.

When I attempt to log in to many sites (Hotmail, youtube, steam community, razerzone, thinkgeek, my bank, etc.) after hitting "login" the page refreshes to show both the username and password fields blank and I am not logged in. I'm running Windows home premium 64bit, and I'm using Firefox primarily but the issue is present in IE and Chrome as well. I think the problem is logging into secure servers, I can view https sites without issue, I just can't login.

I have tried deleting cookies, history etc.
Cookies are enabled
SSL 2.0 and 3.0 are enabled
My firewall is not the issue, I have tried turning it off/adding firefox as an exception
Time and date settings are correct
System restore does not fix the issue
Not Antivirus causing the issue

Any and all help is greatly appreciated!

I realize you are not using IE, but it can't hurt to try it both before and after a reset: Control Panel/Internet Options/Advanced/Reset. You might also check out this tutorial: http://www.sevenforums.com/tutorials/98056-sf-ie-restorator-troubleshooting-general-issues-ie.html

A few sites can be accessed in IE now, firefox is still playing up though.

I'm not sure if this will help, but maybe. Fix: Internet Explorer 9 Does Not Open Links | The Windows Club