"Dealing with Linux Unresponsiveness – Using System Monitor
"First and foremost you can use the familiar System Monitor tool. It looks a lot like the Windows Task manager, only it is better. Not only does it provide you with lots of information about the current state of the computer system, you can use the Processes tab to look for any misbehaving applications and choose to Kill or Stop the process. Both of these operations are very different in the Linux world: stop suspends the execution of the process and kill would close it completely.
"Using the ‘kill’ command
"So far so good, however there are times when you cannot use the GUI altogether. Starting the System Monitor is out of question in such situations. In these situations, you can leverage the power of Linux command line to your advantage. You can enter these commands in a terminal if it is available or you can switch to a virtual terminal using Ctrl + Alt + F1 and logging in using the text mode."
