Black Screen

I am using Intel HD 400 Graphics on a laptop.

When I logout, I get a black screen with no cursor or anything. I have to hard reboot the system to get into linux again.

Working on RHEL 6 (gnome)

What is your default runlevel? If it's not 5, then did you manually start X server? Have you tried accessing one of the virtual terminals by pressing ALT+CTRL+F1 etc? Have you checked /var/log/Xorg.0.log file for any errors?