[whych]

It sounds like you have a problem with the x-window system.
When you choose the failsafe option, login as root and then type sax2 and enter.
This should set up your display. When you are done, exit and you should be able to get to a gui by typing startx.
If all goes well you should be able to reboot and start normally.
Another thing you can do is to check the messages that appear when you boot. Press esc to get rid of the splash screen on boot and check for errors.