frozen centos 3 server

[admin at homemachine.net (Tom)]

Hi,

Is there any way to reboot a server that I can't access via ssh, http, 
ftp or any port? But I can ping, traceroute & nmap it just fine.
I have no idea what is causing this lockup or lock out, even after a 
reboot by the DC there's nothing in the logs to show what happened. :(

regards
tom