How to fix this?

Hi guys, Can i ask something about this? as you can see in the image i have a Generic twin Usb gamepads, when i try to play an arcade game select 2 players the gamepad 1 works without any problems, and when i try to control the gamepad 2 there's no response coming from it. please help!
(Oh! by the way i'm new here so nice to meet guys!)