graphics in low-end laptops are typically controlled by the motherboard, they can die. even if it is controlled by a dedicated card the graphics card can die. It is unfortunate, but your best bet to call the laptop maker and request an RMA.
I am leaning towards the fact that the onboard graphics are dead or the dedicated card is dead because you have already tried connecting to an external source
Or possible hard drive failure, does your laptop whir like it normally does on start up? most have a slight vibration, if that is gone then it is probably your hard drive