I brought a new motherboard today and after installing it and all it starts, all the fans go on, (CPU, case, video card, etc) but it wont give any image neither from the motherboard RGB nor the video card slot.
It could be a faulty motherboard why not go to the place you bought it and exchange it. Most places will let you exchange it for the same make and model even if you don't have the receipt.
Check that all the cables are connected correctly. Are you sure you have a compatible psu? When you turn it on do you hear any beeps? if so how many? Usually more than one means something is wrong.