I'm having trouble finding the key for Sins on my HD, can anyone help?

The details:

I'm studying away from home. I have Sins loaded on my computer and I plan to play with my friends online, however I can't seem to find my manual. I was pretty sure a brought it, but my room isn't that big.. so maybe I forgot it.... Either way, I don't have it, but I DO have the game installed and the key should be in there.

The problem is that I can't update because of the impulse system of updating. It wants me to enter the key, but I don't know it.

It must be stored somewhere. I've checked for obvious filenames and browsed through the registry, so far no luck.

Can someone point me in the right direction?

Thanks

Teljanin