Verified answer

Try with this

EHGY-FZHT-G9XB-GYRE-GED2

Its from an spanish version

Hope it works

Or this

RBHZ-6BHM-1NEC-ROMA-NCER

Try contacting the makers of the game. I'm sure they can help you out, if you did actually lose the serial number and you did actually pay for the game.

Short of buying it again I can only think of the slightly less legal ways of getting one and If you did that there would be no using it online. I can't really say anything else Yahoo don't like it.