I can not log in to my ubuntu 12.4, not even as a guest. Every time i try it push me back to log in screen. And it says something like "suitable mode for kernel not found" I just instal ubuntu few weeks ago and was so happy with it until now. Can someone please help me.
I Solve the problem!!!!
I log in to bash, (Ctrl+Alt+F1)
sudo apt-get update
sudo apt-get install --reinstall ubuntu-desktop
and it worked for me ;)