What killed the video card?

My husband is into online games that require a video card that is above the one that's on my computer (which is the most expensive computer in the house) and was above my daughter's computer that he is using by proxy after his died. Some computers, like mine, have built in video cards, those who don't? Are much easier to replace, which is what he did, he purchased an upgraded video card for the computer he's using after several days of withdrawal from Combat Arms...