Downloading Prison Architect outside of Steam with Steam key

[deadliongamer]

Hi, I bought and paid for Prison Architect with Steam when I had a different computer. I am using a different computer now and for some reason Steam isn't letting me download things, so until I find a way to fix that (which might take a while) I was wondering if I could use a key I got using steam to download through introversion's website. Is that possible and if it is how do I go about doing that?