Wow, why are you still using Firefox 3.5? That version is years old and HIGHLY insecure. What apps are you having trouble getting to accept a modern version of Firefox (From this decade)? I'd try to install the newest version of Firefox (15.0.1) and just see if they work. Containing to use that old of a browser is unwise and you are better off using something else (such as IE9) than something that insecure.

there is some Oracle stuff that needs this exact verion of Firefox. I'm trying to get SharePoint 2010 to auto authenticate for users using firefox.

if you install Firefox 15.0.1, and then change your user Agent to be firefox 3.5, will that work? https://addons.mozilla.org/en-US/firefox/addon/user-agent-switcher. As for sharepoint, I don't know if that's possible, if it uses ActiveX controls.

what does that add-on do? I can't seem to find a detail description of it. Thank you for your help.

You can install the portable Firefox 3.5 or 3.6 version to access websites that do not work with the current Firefox release. http://portableapps.com/apps/internet/firefox_portable/localization#legacy35

ntran, that add-on changes your User Agent to fool websites into thinking you are using a different version of your browser.