Here comes another question about RIFT Keycode

I'm pretty sure I can check that key for you ;)

where did you win it from?

You should be able to redeem it from Rift's official site. Log into your account an apply the code. That's how I redeemed the key I bought from Amazon.

By the way, it's an excellent game. I played it for about 6months before I had to cancel my subscription

Try redeeming it on Steam if it doesn't work than it's not redeemable on Steam.