I am running a red hat 6 box that is being used to server e-mail and it has been working fine for about 3 weeks when I decided to restart it this morning. When Linux boots, the startup proceedure is normal except it tries to load INIT: Runlevel 3 and hangs. The only keyboard response I get from the machine is ctrl-alt-delete, which causes the box to go INIT: Runlevel 6 and then hangs. There is no GUI on this machine, just Red hat command line. At this point I have to turn the power off to the box. Any suggestions?

How do you load into different runlevels?

not sure on the main problem, but you can load different runlevels at the lilo prompt if your getting one.. like this:You can try using runlevel 1, single user mode, to try and get into the system to check things over and fix anything....

Once you can get into the system (via runlevel 1 or a boot floppy, you could try selectively disabling the services started by init in /etc/rc.d/init.d if need be. Also check your logs to see if any error messages managed to get written before the system hung..

Here's
a blurb from Redhat's support site which describes the boot sequence in some detail; perhaps it might give you some ideas on where to look for the problem.