Go2Linux posted a guide about killing a non responding application in Linux

I've seen this very few times in Linux, but yes sometimes it happens, an application or process stop responding and gives you no other option than to terminate it.
In Windows, you press ALT-CTRL-DEL then look for the not responding application and close it, if you are lucky enough and Windows is still responding.
To do something like that in Linux, we will use the console, it is the best way, because if you are on your really bad day, you may have even X not responding, so you will have to another terminal. Pressing ALT-CTRL-F2 will do the trick, if even that is not working you can also go to another computer and ssh to the PC with problems, this final option never failed to me.

  How to kill a not responding application in Linux