how do I stop firefox from automatically starting on mac

So, it's really annoying how on this MacBook firefox starts up every time I log in. I have go over and click it to tell it to go to hell. Of course the controls for this sort of thing are all hidden on the mac. What is interesting is that there is a chorus of wailing on Google regarding this issue, replete with insinuations of malfeasance on Mozilla's part. Answers to other people's questions included where to find the startup controls so that it can be disabled there (it wasn't enabled there for me), how to click on the system tray icon to directly affect this setting (it wasn't set there either), to obscure bugs in unrelated software that was causing the problem (but... it's supposed to just work). The best links so far:

The basic suggestion:

http://support.mozilla.org/en-US/questions/738485

The forum thread where much smarter people post the obscure solutions that worked for them:

http://forums.macrumors.com/showthread.php?t=204670

Mac task manager

Trying to kill a program stuck on an infinite Rainbow Wheel wait, I'm not sure what the process name is so ps -eaf and kill won't help me. Fortunately, OSX has a task manager GUI like Windows, it's just hidden like everything else on a mac. To get the GUI task manager, just hold down option, command and escape at the same time.

From here:

http://forums.macrumors.com/showthread.php?t=100694

No dos2unix for mac OSX

Nope. You've got to find a third party substitute, download a gnu or BSD version and stick it in /usr/bin, or do conversions much more manually. Most sites I've found recommend the latter with this command:

cat $offending_file | tr '\r' '\n' > $new_filename

for instance:

http://hints.macworld.com/article.php?story=20031018164326986