If my assumption is right and you were planning on running UE4 on this machine, you can forget about it right now. Your video card is unsupported, there’s not enough RAM and the processor is way too weak.
While this does not explain why you can’t run the launcher itself, you will be unable to accomplish anything else anyway. It’s a terrible idea to use a computer like this for production of any scope; even if all you have in mind is just messing about in the editor.