What do you mean by Circling? XD

When I play a tank combination such as firebird and viking, when I move and turn the turret, and shoot something happens, It seems to lock when I do this which makes it very difficult to play in games in. What exactly happens is that if im holding space and moving it will lock and i cant move in a new direction or my turret unless i release space. I'm running windows 8.1 which I think may be a large impact on it. But when I played on Windows 7 I got it much less consistent, but still did. I have noticed my friend would get this but it was rare for him. I would like ALL help. TY :P