I have bought the game, installed and activated via steam

Why does my computer say the game is not installed anywhere?

Surely I don't have to go through steam every time I want to play the game?>

There is no desktop shortcut and the game is not in c:/program files or anything like that

How do I just play through my desktop, without internet connection or steam?

Also, where is the data editor. Why change things, it's no so complicated and stupid