Installing newer version of Mozilla, passwords?

Hi,

at first I had Mozilla 1.something and then upgrade to 1.2.1 and it 
automaticaly kept the settings including my password settings.  However 
I am afraid of deleting 1.1? for losing the settings.  I am thinking of 
upgrading to 1.4 now but I am still afraid of the passwords and I don't 
want to risk it, but at the same time I don't want to have 3 mozilla 
browsers installed!  Is there a way to install the new one and keep the 
old settings (especialy passwords) and without fear uninstalling all the 
previous versions of mozilla?