What to do when ubuntu freezes?

What to do when ubuntu freezes?

 Well there in an easy way to restart your system without rebooting the machine.

To do this we will need to set-up a new shortcut.

Go to keyboard settings:

Then go to Keyboard layout, Options, Key sequence to kill X server and enable the tick as below:

Now every time your computer is not responding it is enough to press Ctrl + Alt Backspace and you will be given with the very fresh ubuntu session (particularly important when the computer is heavily loaded with penetration testing applications)