I'm running CentOS 4.7. I'm having the following problem:

On logging out from a GNOME session (Actions -> Log Out -> Log Out), the computer simply hangs. The Caps Lock and Scroll lock keys on the keyboard are flashing. I can ping it from another computer, but services like VNC and Webmin won't work anymore.

What should I do to troubleshoot the issue? Which log files should I check?

It only started acting like this yesterday. The last thing I can remember doing that could've caused this is when I ran a "yum upgrade" and updated some packages at the same time. Mind you, I don't log out a lot though. I usually start it up, leave it on for a long time, shut down (sometimes), or start it up after recovering from a power interruption (sometimes).

Thanks,
gillbates