Turn your computer off, Turn it back on usually there will be a message saying press f2 / delete, it various on your motherboard but the most common are f2 and the delete key, so basically spam one of those 2 on start up and you should get into your BIOS, Now if you don't know what you are doing here don't just go around changing random stuff you will likely mess something up big time, You are basically looking for something called onboard graphics it should be set to disabled, as most motherboards will auto disable this feature if you have a dedicated graphics card installed.
Once you find it go ahead and set it to enabled. and save and quit.