Can I install a video card on a Lenovo B50 desktop computer?

I'm not super computer savvy, but I play a lot of videogames online. I just bought a Lenovo B50 desktop computer. It has no tower.

It doesn't play games as smoothly as I would like, and I need to know if I can put a video card in it. I have already checked and it has internal graphics. If I can't install a video card, what can I do to better my graphics?

http://shop.lenovo.com/...02035232:s
If that is what you have, it is not a "desktop" with no tower. It is an all-in-one computer like a laptop that does not fold up and needs a power cord. And you can't add any internal graphics device to it. Worst of desktop and worst of laptop qualities combined.
You might add a docking station that could have a better graphics device--connected to HDMI IN port or to a monitor.
Or you could get an external PCI-e X16 slot adapter and power supply, connected to internal mini-PCI-e slot on motherboard where the wireless adapter is. Then you can run an exertnal monitor or the internal screen with HDMI in. Only a few hundred more than the video card.
http://www.banggood.com/EXP-GDC-Laptop-External-PCI-E-Graphics-Card-p-934367.html?currency=USD&createTmp=1
http://www.hwtools.net/Adapter/PE4C%20V2.1.html
If you want to play games with a better graphic response--get a desktop with expansion slot(s).

You can't.

I look into the all in one pc it's just the power requirements to install a good gpu even a low profile one if there's a pci-e slot inside the pc, i really think these all-in-one pc's are good for multi-tasking than gaming a friend of mines told me that he use low settings could seem to adjust the internal gpu settings to make the game run smoothly