I have marked the thread 'solved' for you to discourage new replies. The thread will close itself in a reasonable amount of time. Meanwhile you can still come back if the problem decides it isn't...
If the HP-UX box is not pingable, and its NIC access is slow then I suspect the NIC hardware or the LAN cable is broken.
Does a
/usr/sbin/lanscanwork?
If yes, on all lan devices that are in UP...
I am in no way a "HP-UX master", but this sounds suspiciously like a resolution problem. Most times when the system is fine but network response is infinitely bad it is for one of two reasons: