Does anyone know, if I bought a used fs one flight sim, would I be able to install it? I know it probably has a keycode.....can anyone tell me?
Thanks.

Call Horizon Hobby at 800-338-4639 and check with their customer service folks. I know Real Flight has an "unregistration" process so you can transfer ownership of your sim package to whomever you sell it to. Hangar 9 will most likely either have a similar process in place, or won't require it.

I have FSOne and it does have a activation code. Now I don't know if you can call Hangar 9 and see if they can help you. I suppose it will depend on if the other person took it off of their computer. Probably a uninstall process.