Oblivion

Hi there. I got this game, and I am in the tutorial. I have an Iron Key to open a door, but I can't figure out how to use the key on the door. I tried putting it in my hotkeys, but every time I use it it says that the item cannot be equipped -- though I am right next to the door, it doesn't open.

Any help would be appreciated. Thanks!

I thought you just tried to use the door and it automatically checks to see if you have the key.
If you do, it opens, and there's a notice at the bottom saying "You used Iron Key to open the door".