Could you try creating a new settings folder (a new Firefox profile)?

The first step would be to make sure Firefox is not running in the background. Press Ctrl+Shift+Esc to launch the Windows Task Manager and click the Processes tab. Find any firefox.exe and "End Process". Repeat with any plugin-container.exe.

Next, Start > Run

firefox.exe -p {ENTER}

Do you get the Firefox Profile Manager? If so, don't delete anything, just click Create Profile, accept the default location, and give it a name like TEST. Then Firefox should start up in the new profile. Does that operate without crashing?

By the way, in case you haven't seen these articles, but I bet you have:

• Troubleshoot Firefox crashes (closing or quitting unexpectedly)
• Firefox won't start - find solutions

Here is the report for the crash ID you furnished:

https://crash-stats.mozilla.com/report/index/05003ed8-e9ad-40d2-832a-18fcc2120628

Firefox 13.0.1 Crash Report [@ @0x715b9e59 ] 

I don't see anything useful but maybe someone else will?

You said (in "more system details) that you tried safe mode and it crashed in safe mode too. Now when I try to start FireFox it does nothing at all.

Try rebooting the computer, and then try starting in Firefox Safe Mode. Does Firefox start up? Does it crash? If Firefox still crashes, could you post another crash report ID? Maybe it will be more helpful than the last one.

If nothing else in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article was helpful, you could also check this article for other ideas.

• http://kb.mozillazine.org/Firefox_crashes

Thanks for all the suggestions. I simply did a clean install and everything appears to be fine now. I just didn't have time to troubleshoot this issue--too many other thing going on. I think it was FireFTP causing the problem. I installed FileZilla instead. I really didn't like the idea of my FTP client as a browser plug-in anyway.

Thanks again.