Ping problem

[sos]

I am having an issue with a windows 2000 machine that cannot
access isp's mail server. Pinging mail server gets no reply.

All other clients on lan can access mail server no problem.

I have booted off of a knoppix live cd and can telnet into mail server and ping it so I am sure it is a software problem.

The computer in question can access the web normally.

There is no software firewall on this machine.

A full virus scan was done in safe mode with Antivir, Kaspersky online scan, and trendmicro housecall. No baddies found.

I am pulling my hair out trying to figure this one out.
What could be causing this?

 

[sos]

Ok this is weird I noticed that for some reason someone had set a static ip under tcp/ip properties. I set it back to dhcp
and now it is working.

Weird because no dns info was set. Oh well working now.