navx problem

I use Netscape 7.2 on Mac OS X Panther (1.3). I wanted to try Firefox,
but it does not work with Yahoo mail.

Netscape works fine except it occasionally goes south (hangs)
apparently related to particular internet sites. I notice that when it
hangs, a process has started called "navx" that takes 50-60% of the
CPU, which is ridiculous. Usually, this process does not show up with
the "top" command. Perhaps it is there but at a very low level.

What is this process, and why does it hang for certain sites? Thanks
for your help.

Shoot me an email if possible. 

-Tony
amannuc <at> yahoo.com