Laptop question

This is a piggyback to my previous question, but here goes:

Is it true that most standard middle/low end laptops won't run games like call of duty because they don't and can't have graphics cards? For example, I'm looking at this computer: HP - Pavilion Laptop with Intel® Core™2 Duo Processor - Black - dv6-1355dx

And I've been told by a non-computer expert that you can't put a graphics card in without voiding the warranty because it would require taking soldering something or something like that. He said if I tried to put call of duty on the computer, it wouldn't work because there's no graphics card in the computer. I've played an older version of Call of Duty on my piece of shit Dell Inspiron with 512 Ram and Pentium 4 Processor. While it wasn't great, it worked. I also play the hell out of some crossfire on this same laptop, so I wonder why he says I can't play Call of Duty on that machine? Is he accurate? It seems like a pretty good machine for the money, way better than what I currently have. I understand desktops would be better for gaming, but I can't afford both, and I need a laptop and can deal with lower gaming performance, since it's not the primary use of the computer. Anyways, any info/insight/experience on this would help. Sorry this was so long, but I figured if it's long, only people who really understand will take the time to read all this. Thanks!