Multiple questions. Because I haven't done this on a pre manufacturered PC before. But im going to be upgrading my GPU and i need another PSU to fit it. I wanted to know if this was possible. My brother says no but everywhere else shows no reason not to. Its a stock Gateway (I'm aware it's an abomination). I need a 400w+ to go in it. Is this possible and what will it take. Thank you. And please forgive me for my stupidity on the subject I'm just used to custom builds.