I have Mac OS 10.4.11, and when I tried to open firefox today it wouldn't do anything- no error message, nothing. So I went to this site to download it again, and all I could find was Firefox 4.0, which apparently is not compatible with my OS. So all I want to do is download an earlier version that IS compatible, but I cannot find anything that would allow me to do this. Does that mean I can't use Firefox on this computer, or can someone help, please?