SYSTEM HANG - NATD running FINE

[Ben and Jen]

My system has recently "locked up" after 65 days uptime, running only natd for my local network.  Natd still works fine and routes information properly - but I am no longer able to telnet or login to my machine even from a local console(alt f1-fx).  After I enter my root or user name at the login - it just hangs there.  When I telnet in, it does not even prompt me with a login.  

Anybody ever had this problem before?  Any suggestions on how to recover my system without rebooting? 

Any help appreciated.

Thanks, 
Ben