Hello Dnak,
I have a sense this is some hardware issue caused by the built-in keyboard in you laptop. I'm not going to deep into the operation of keyboard, in simply when you press one key, it makes a signal, and when you press other key (for example Shift) it modifies the signal. In your case maybe the combination of 1, 2, and 3 buttons causes an Enter. To find is it caused by hardware, you should to open a notepad/word/any text editor, and start pressing 1, 2 and 3 buttons just like you would make it in the game, and if it adds new line /Enter/ then the problem is in the keyboard itself.
In that case I think you can try 2 solutions, first is using an external keyboard which probably won't have this behaviour, or the second one remapping some of your keys (however that's not sure it also won't cause some different side effects). For this you can try the program called
KeyTweak and set up by using the
instructions here.
If it isn't any hardware related stuff, then still possible your laptop have some macro program or similar by default (probably something from your machine's manufacture). You should to check any of them in the notification area (next to the clock) firstly, then under the
Processes tab in the task manager, if you can find any, simply close/kill the program and check if this problem still persist in the game.
