Linux correlate of Windows' Ctrl-Alt-Del

Sometimes Linux appears to come unstuck. In windows, I used to use Ctrl-Alt-Del to try to expunge offending applications. I know there must be a linux correlate of this for similar emergencies. Perhaps there are several. Can anyone enlighten me. I know about the Process Management tool, but what if nothing responds to a mouse click. What should I try before hitting the restart button. I have SuSE 7.1 Thank you. -- Dan