Way to check keys for validity

And that's the cause of our drop key thread :-)

That doesn't work either.

Nope. It will just tell you that you own the game, won't matter if the key is already used or not.

Nope. I just tested this by trying to activate a The Last Remnants key I used for a giveaway and I got the "Product already owned" message.

F+ for volv
that works, once the key is entered it shows already owned > click next and install that very game you tried to redeem
(next button + install info, might not show if the game is already installed) ... that way you would know at least its the
right and valid key - although usually you don't have the chance to test that, besides what it doesn't let you know is
whether it has been used or not lol