In case you are using "Clear history when Firefox closes":

• do not clear the "Cookies" and the "Site Preferences"

• Tools > Options > Privacy: History: [X] Clear history when Firefox closes > Settings
• https://support.mozilla.org/kb/Clear+Recent+History

Note that clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, and passwords.

cookie destroyer What is the software exactly, (Full name, version & home page may help) If you need help with it you are probably best visiting that software's home or support site.

This article is being re-written at the moment, but still should be an interesting read

• Where are my logins stored?
• and general info on cookies
  Cookies - Information that websites store on your computer
  Permissions Manager - Give certain websites the ability to store passwords, set cookies and more

It gets rid of publisher's clearing house, it causes facebook to think I was a texas login unless that is based on my cell phone being out of oklahoma, I already fixed the cookie settings like you say, I have vista & firefox 18 can not afford anything else, cookie destroyer & other site settings will not activate,