First of all, I really hope you're not trolling.
A video card (also known as a graphics card) is a piece of hardware for your computer. With a better video card, you can
-Edit/Render photo/videos faster
-Do more in-depth editing in photoshop
-Watch movies in more detail without lag/buffering, etc
-Play more detailed games on higher resolution and higher graphics settings
Good graphics cards have lots of dedicated video memory (ram). For example, a graphics (video) card with 1gb of dedicated memory will play better quality games. It also depends on the model, brand, etc.
The error message you got means, depending on the game, that either you have a really old computer (at least 6 years old), or a horrible integrated graphics chip.
A computer with integrated graphics doesn't have a physical graphics card, but instead shares system memory from the motherboard with graphics. It doesn't have any physical dedicated video memory. Therefore, it sucks at gaming, etc. If you have a laptop, there is nothing you can do but get a new laptop with a dedicated graphics card, or a desktop with a dedicated graphics card. If you have a desktop, you can either get a new graphics card and put it in your computer (which might require a new motherboard depending on how old it is) or get a new desktop.
If your computer is old, get a new one. You won't be able to buy a new graphics card for it because it's hardware will be outdated and will most likely not support the graphics card. If you don't want to spend a lot of money on a new computer, get a barebones kit, which is a kit that includes most of the parts necessary to run a computer (case, processor, ram, etc) but you have to put it together (some are pre-assembled) You might need to buy a couple other things to make the computer run depending on the kid, including a dvd drive, a psu (power supply, harddrive, etc. If you plan on doing this, check out tigerdirect.com and newegg.com
Overall though, if you want to play the game you most likely need a new computer. Thats really the only way to play it (unless your computer is probably no older than 3 years old. In that case, you can just buy a new graphics card. $100 will get you a nice one, capable of playing most modern games, but you can get one for $30 that has some potention on the listed websites above.
More info would be VERY helpful in determining the best option for you is, including
-Computer
-Age of computer
-Computer specs (processor, ram, graphics, etc)
-What game(s) you want/will be playing on the computer