Can Firefox be updated without affecting the rest of my system?

[Josef Lowder]

Is it possible to upgrade Firefox without causing any effect on my
operating system?
And if the upgrade does not work, could I restore the old Firefox version?

For reasons to long to explain, I cannot risk upgrading my Linux
operating system.

Linux localhost 2.6.12-12mdk #1 Tue Sep 13 10:46:25 CEST 2005 i686 AMD
Athlon(TM) XP 2600+ unknown GNU/Linux

Firefox help shows 1.0.6 and this:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050921
Firefox/1.0.7 Mandriva/1.0.6-15mdk

I just don't understand how separate Firefox is from the rest of the
operating system
and how risky it might be to try updating Firefox.  Could that be done
with zero risk
to any disruption of my operating system?