Your post implies this happened once. My answer therefore is that your computer probably wasn't in the mood to play CS:S and decided to crash to give itself a break. It's quite a common prob with lazy computers.
"Its only when you look at ants closely with a magnifying glass on a sunny day that you realise how often they burst into flames"
More like rebellion, PC's have a mind of thier own...
<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>