hey.. i have a 900$ compaq its got a decent proseser n plenty of gig n stuff, n i was wondering if i got a external graphics card could i plat call of duty. or is any 1 sellin a cheap comp

If you want to game, buy a Desktop, or a console.

Not always true, mine can run a fair few games, not on highest settings obviously but still smoothly and a fair few newish ones, like obviously it won't run new release top end games but it can handle team fortress 2, world of warcraft, sims 3 etc. so i'm happy enough with it.

To the OP, if you could list a few of the specs of your laptop it might help, as well as which call of duty you were hoping to run, since well the first 2 don't have the highest requirements, however something like say modern warfare needs a lot more grunt to run. But if you want to check I've always found this site to be pretty accurate, so far no game it said would run, hasn't

http://cyri.systemrequirementslab.com/srtest/

My laptop runs any game currently avaliable pretty well, and it wasnt that expensive either at $1800

The only downside is the screen is 15" rather than the usual 22" or so of a desktop monitor

Well if you like to play CoD on laptop you wouldn't enjoy that much since it needs a very good video card.
I agree with Chris, buy a desktop or console for gaming.

console all the way.. never have to worry about upgrading all the time