My mouse is not locking to at least 2 of my games

i have 2 games i have been want to get back into playing,they are Dead Island and Fallout:NV,but i have a 3 screen setup,and i want to play the game on the center screen and run other stuff on the other screens(like pandora),but when i try to play them they start up just fine but while i am playing and when i move the mouse it moves right off the center screen on to the other screens and if i click it acts like i alt-tabbed. 

So far it only happens with those 2 games but there may be more lol.

Do you guys know how i can fix it?

I believe there are programs that can lock the mouse to a certain window if you need it. Not sure though.

check your game settings,i know that there is a ''windowed fullscreen'' mode for users who use multiple screen setups and this option does exactly what you mentioned,acting like you have alt-tabbed i do know that some games do support this setting.