According to the Hardware & Software Specifications page, you need to have a DirectX 11 compatible video card on Windows. Do you?
If you do, have you run your windows updates AND installed the latest video card drivers?
If you don’t, then if your computer has a graphics card expansion slot, I would buy at least a $150 new Nvidia graphics card and install it. (I hear a lot less complaints about Nvidia cards and UE4 at the moment than the AMD cards).