Lenovo Y50's hinge applies on the screen lid quite extensive load. So, this laptop often has issues with the hinge screw posts inside the screen lid.
One possible way of dealing with this issue is shown below.
The vast majority of screw posts in Lenovo Y50 are made of a plastic post and threaded expansion insert fused together. It's not a big surprise the threaded insert can easily come off due the insufficient plastic quality. In the video fragment you see the screen lid screw posts for the right hinge having this problem: