unkillable process

[BROWNH]

Can't shut down a session of Netscape. The Netscape window has no content.
I can minimize it and make it full screen, but close does not work. I 
killed the xterm from which I started the session. I tried to kill the
thread, but nothing happens.

Here's the thread info:

process number  21005
TTY             ?
status          S
Time            121:23  [sic!]
address:        /opt/... [etc.]

I can start another Netscape session, and it works fine. 

Haines Brown