Can this laptop play left4dead?

Your laptop should be able to handle left for dead fairly well, depending on your settings of course. The processors and everything else is clear. The only choke it has on it is the video card but i think at medium settings, it shouldn't be a problem. Make sure to check your video settings carefully. Anti-alising will kill your gaming experience on that laptop if you don't turn it off. Just don't try to run too much while you're playing. I had a laptop similar with a step down from you and it ran well. Have fun gaming.