[Boris]

Do you have to buy multiple keys in order to run the client on another window? Dual boxing?

[Hanabira]

Each Window needs an own key so yes for dual boxing you need two keys

[Cichard]

1 game key 1 bot key per instance of the game client you want to run.

[Boris]

1 game key 1 bot key per instance of the game client you want to run.

Are the keys bidden to a certain PC or any PC can use it just amount of logins is restricted?

[HansW]

we don't bind keys to PCs, so you can use it on any PC you like, just only one at a time.