Sounds like something has gone hinky, alright.
Consider logging into single user mode and backing up all your important things.
Also take a look at the output of the 'dmesg' command, /var/log/messages, and the X log in /var/log directory.
See my link below or the post :
Log into single user mode
PS : you can run :
# /etc/init.d/network start
# /etc/init.d/sshd start
...to get remote access working in single user mode. Probably makes it easier to back up your files.