You should be upgrading to a secure and supported firefox 7.0.1 not to an unsecure unsupported old version 4.

Consider trashing the current instal and doing a clean instal. Do NOT uninstall or delete the user settings. Use Mozilla as the site you download from, and not some unapproved third party site.

See (and also note the links availablle from within those articles)

• updating firefox <-- (blue) clickable link ---
• How to download and install Firefox on Mac
• firefox crashes

I don't know anything about Firefox 7, but Firefox 4 is the version that is advertised when I try to update via Firefox.com. And when I go to that site, it says "Unfortunately the latest version of Firefox isn't compatible with your computer's operating system." But as I stated, I am using OS 10.5.8, which is listed as one of the operating systems supported by Firefox 4. So I don't know what the heck is going on or why it won't let me upgrade.

Not when I go there it ( firefox.com) links to http://www.mozilla.org/products/download.html?product=firefox-7.0.1&os=win&lang=en-US so in my case it is offering the Windows version 7.0.1

Try instead the link http://www.mozilla.org/en-US/firefox/all.html

Well that doesn't work either. Says 7.0 is incompatible with my hardware. So my question remains, how do I get 4.0 to work with my computer? I have the necessary OS, but it still won't work and now firefox crashes every single time i try to open it. I have to use Safari to browse. What gives

Have you tried starting firefox in safe mode ?

• but make no changes in the window with listed option, just click on continue
• use the default theme
• if the above does not work, then also whilst in safe mode disable all plugins

I do wonder if malware may be a problem.

• see is my firefox problem a result of malware

Have you tried reading the article I linked to in a post above, firefox crashes and tried to obtaincrash IDs ?

• also see http://kb.mozillazine.org/Breakpad#Location_of_crash_reports

Sorry, Firefox 4+ versions aren't compatible with PPC Macs.
http://www.mozilla.com/en-US/firefox/4.0/system-requirements/

For older Macs that aren't supported in Firefox 4 / 5 / 6 /7, try TenFourFox for PowerPC's running Mac 10.4.11 & 10.5.8 .
http://www.floodgap.com/software/tenfourfox/
http://code.google.com/p/tenfourfox/downloads/list

Thanks for stepping in Ed, sorry for misinforming you rustysheriden, I was forgetting the processor.

The Firefox 3.6.23 version is compatible, still secure and supported. (Probably only until Firefox ESR comes out) Some of the third party offerings could possibly be at present based on insecure firefox versions, if they are used it will be worth keeping an eye out for updates. And maybe taking additional care with ensuring you have backups and a recovery strategy.

Firefox 3.6.23 is available from :

• http://www.mozilla.org/en-US/firefox/all-older.html
• as mentioned in installing a previous version of firefox