Facebook totally frozen -- can anyone help?

Hello, I am new here. I have had Norton Internet Security since 2005, renewing it yearly. Current version is 8.0.7.1, and the current version of Norton AntiVirus is 11.0.17.1. I have the most recent versions of Firefox and Internet Explorer. My problem: Ever since I joined Facebook in July, it has always been “balky.” Messages would not go through until I reloaded the page, or clicked “send” 4 or 5 times, etc. In the past few weeks it has gotten steadily worse, and now Facebook is almost completely frozen. It will let me log in, and I can view things – inbox messages, updates from friends, friends’ profiles, etc. – but cannot input anything at all. I did a search of these forums and found these results: http://community.norton.com/norton/search?submitted=true&q=facebook . I took the actions recommended in those threads (Intrusion Detection > Advanced > Signature Exclusions > uncheck everything starting with “HTTP Facebook”) and they have had no effect. Once in a great while, my account will un-freeze for a few minutes or a few hours, for no reason that I can fathom, and then freeze again for no apparent reason. This is a shared home computer, and the same thing happens on my partner’s side. Facebook Tech Support’s advice has been pretty much limited to deleting cookies/cache/browsing history. That has not helped either, and they appear to have given up trying to help. From reading these threads, it appears that people have gotten help for problems with Facebook similar to mine, but I haven’t been able to find anything to fix my particular problem. If anyone can help, it would be greatly appreciated. Thanks, Bruce