Anyone Own Metro 2033 for PC?

Hey guys. I was looking into downloading this game because I am a fanatic of survival/horror games. (Yes I know, why are you downloading it, buy it like the rest of us... well, I got layed off so Im cutting corners.) I was wondering if anyone could post their USED serial number. Yes, used... thats how I need it. Any help would be much appreciated and would save me the trouble of keyloggers and virus