But then you have to login and type "top", this will show all your active running processes, and the ones that is consuming the most memory will be at the top. Lets say "wine" is taking up all your system resources, or is just whatever, you exit out of top by pressing ctrl + z, and top will shutdown. Then, type "killall -9 wine" to kill that process. Put anything else for wine, since that may not always be your problem.
NOTE: If you deicde to kill x. It will just restart X itself. It does the same thing as loging out to the login screen, but its refreshed. I suggest you do that instead of pressing ctrl + alt + backspace, since that seems to hurt your graphics card. (abrubtly ending the x session while in x hurts your graphics card. In a terminal, I don't believe it does)