[NaS]

Well since you can still press ESC, type in chat and anything else (You can even move, but wont see it), just press CTRL ALT DEL (or ESC) and wait for it, then kill the process - done. Even worked on my 2005 PC (Just don't spam keys like a kid). The overheating stuff is, well possible but you should think about buying some cooling (or better a new PC), anything else could also cause this then (even windows...).
When a system overheats bcuz of GTA San Andreas, how will it handle any other game which is from 2006 or later?