Laptop Light Screen of death?

I ever end up playing video games by my Vaio laptop. APB Reloaded, garrys mod, assassin's creed and Doomed Isalnd. And almost everytime, eventually, my computer screen starts going white around the sides and the eyeshade freezes, the sound then gets all buzzy and the white crawls across the surface then shuts the computer downbound. I don't know what to achieve to fix this! Please help! I even checked with my regional PC store and it was fine!