I got in fine with IE and Safari.
You tried several browsers so what's the common demoninator? Java maybe? Your router settings maybe? Firewall maybe?
Try again to dump your cookies, delete apps all Java in Add/Remove Programs, use the Fava Control Panel > General tab > Temporary Files Settings > Settings button and Delete Files - put checks in both boxes.
Download new Java from
www.java.com. Restart the computer.
If that doesn't fix it, look at your firewall and router settings. Are you blocking anything? Did you make any changes since when you last logged into the site.