I have an old version of KSP (Beta version)

[Man O' War]

I have an old version of KSP (Beta Version) on another computer. How do I get KSP on a new computer?

[Plusck]

Just copy the whole folder across? KSP doesn't appear to require any kind of install into the OS that isn't managed on-the-fly on starting the game.

Or you buy it, download the full game and wonder why you didn't before

[cantab]

If you got KSP on Steam, you can install Steam and your games on any PC.

If you got KSP directly from Squad, you can log into your account and download it. If you forgot the password look for a reset option.

Not sure about GoG or Amazon.