• "Clear the Cache": Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"
• "Remove the Cookies" from sites that cause problems: Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

• Don't make any changes on the Safe mode start window.

See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems

All I did was clear the cache and delete all cookies with the text "facebook" in them. I don't know which one caused the problem. The instructions for clearing the cache and deleting cookies did not match my version of Firefox but I was able to figure it out. Thank you much.

You're welcome

I'm curious where you found Options if it is not in the indicated place or did you use Tools > Delete browsing, search and download history on Firefox ?

Tools>Options>Privacy>clear recent history And Tools>Options>Privacy>remove individual cookies

Which were the only things available in my version of FF (3.6.12)