Ooookaaaayyy, deinstalling on Laptop fix it...
Gaming PC is now running without reinstall.
That´s a terrible Gamer unfriendly way to trust your Customer.
I have one Steam Account why should it not possible to "play" on several Assets the Game
you need to understand how steam works, this has nothing to do with this site or company either, it's steam, the item you need to research is called steam guard, steam guard is enabled by default on all accounts made on steam, it has been setup to protect your account and for that reason you need to give each pc you own which has access to steam a given name a unique name and assign steam guard permissions for it to work, with this done, each pc asset you own will be enable one at a time to access your whole steam games list, but you will never be able to use more than one pc at a time, each pc asset you own will be need to be logged off and out before another one is used logged in and started, or you will get a error, each time you do this unless you set it up correctly you will need to manually assign a code which is sent to your email address when you first setup steam, you can even load steam onto your phone, even if you can't play any of your games on it, same as other devices etc, but if you forget it's logged on and try to do the same with a pc, again you will get an error, as far as i know, there is no way around this, even using family share for pc in the same house on the same ip, as each asset as a name of it's own, steams see's each device as a different pc, and as all pc's on a network have to have a different name anyway, or they would class, again no work around to do this, owning a game doesn't mean you can have 2 players using the same one game over lan, each pc player needs to buy a serial of there own and also each has to have there own account on steam, this is how steam works