Somebody is hacking me; what to do?

[Daniel Mashao <daniel@vitasat.ee.uct.ac.za>]

I am getting emails from some fool saying 
	Ifwewerehackerswedownyourdumbass
which means "If we were hackers we down your dumb ass"

The emails are generated from within my system. The problem started when I
logged into one of my old machines and ran "last -10". I was suprised to
see a user by the name "nis2". I knew I was hacked. I proceeded to delete
the user and couple of other users. The hacker got angry and started
sending me emails. The problem is that the emails seems to come from
within the system. 

Any boffins out there may want to know that the loggins seems to come from
195.146.109.166. When I telnet this address I just get logged in. 

Any advice for me?

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Daniel J. Mashao	      	
Electrical Engineering                          daniel@eng.uct.ac.za
University of Cape Town	       	            http://www.ee.uct.ac.za/~daniel 
Rondebosch, 7700, S. Africa         (w) 27+21+650 2816  (h) 27+21+705 8469
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