3.4 GHz Intel Core i7
4GB 1333 MHz DDR3
I would suggest that you download the version of Firefox that you want, and install it manually. Why do you want Firefox 4.0? The current version is 15.0.1. You can find any version you want here:
I did'nt realize I was so far behind on the versions. I just assumed firefox was keeping me up to date in the background. Is there a link to instructions on how to load 15.0.1 manually?
1. Download a copy of the latest firefox from http://www.mozilla.org/en-US/firefox/all.html
2. Trash the current Firefox application to do a clean install.
3. Install the version that you have downloaded.
Do not select to remove your personal data, your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks or other personal data.
see also: Installing Firefox on Mac