I bought Asus motherboard but it show green and square blue screen in middle on start the load ???
Yes the Logo appear fine when HDMI is connected to Motherboard. But green and screen and line shown on start when my RX 580 card is connectedJust so you know, there isn't such a thing as PC with a specific brand.
PC's are not Apple. The logo at the start is just the motherboard brand/details loading.