[CentOS] Hanging @ Sendmail During Boot

Hi All,

I have a coupla queries about my 2 latest installs of CentOS 4-3. When I 
first installed and logged in as the initial user, everything went well, 
and the system was fast. A reboot, and 2nd login gave the same. But, 
upon connecting to the net, the system hung at sendmail for almost 
4mins, and then gave an error at login about not finding the host, and 
that Gnome may not work correctly, with options of Continue or try 
Again. After that, the system has become extensively slow. Any ideas why 
this would be this way? This is the 2nd machine, different locations, 
different media, that this has happened. Rather annoying. Cheers.

Mark Sargent.