The login manager program which runs in your default run level is crashing. The inittab entry respawns this program and it crashes again.
For run level 5, it could be kdm/gdm, etc. or it could be a problem with your xorg server.
Try logging in to Single mode. Add the kernel boot option "S" or the word "Single" in the grub menu. Then check which is your default run level in the /etc/inittab file:
id:5:default
or
id:3:default
Code:
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6
# Run xdm in runlevel 5
# xdm is now a separate service
x:5:respawn:/etc/X11/prefdm -nodaemon
You might have xdm, gdm, or kdm for run level 5. Validate the package that supplies the program.
e.g. rpm -qV kdm
A corrupt corrupt binary, or invalid config file could be the cause of the problem.
Also try "startx" and see if the X server starts up.
