What do i need to prevent my laptop from randomly dying?

I have a Gateway p-7811fx gaming laptop. and its been working quite well, besides when i play the newerr games, such as Call of Duty: Black Ops. If I play on all high settings, it will let me play for about 15 minutes before i notice that my laptop charger stops getting electricity. then after that my laptop will just shut off. and the charger doesnt recieve electricity until i unplug, then plug it back in. I dont know if i need a surge protector, or what. And i know its not my drivers. i have a clean install of windows 7 ultimate 32 bit, with all latest drivers. And nothing out of the ordinary besides the whole charger thing. Oh and i should mention that while i play the games on lower settings I can play for hours, and non of these errors occur. but seriously, who wants to play on low settings? Isnt that the reason we all switched to pc for gaming? (well besides for the awesome controls) Any help will be satisfactional in my opinion. thanks in advance =]