I heard this is an issue of many people, and if you lost it, it's still got to be in your location of the house/place unless you brought it outside or let someone borrow it. So keep rummaging and you'll eventually find it. However, if you feel like you threw it away or something, then you're at a loss. However, if you want to get the full version really badly and don't want to pay, you can always step over on the illegal side--Oh, pardon me, I don't think I should say that all, it's Taboo...Well...not really. >_>
Just crack it if you must. :3