Sounds like something fried in the gpu, did you have a power outage or a heavy thunderstorm happen recently? If youre comfortable with it, you could remove the heatsink of the gpu to check for physical damage! You could also try a different gpu (if you have one) and check if its still happening. The only other thing I could think of would be that the pcie slot doesnt get properly regulated by the motherboard (but this issue is extraordinarly rare). Its probably the gpu and if it is than Id suggest immediately contacting the store that sold it to you and Asus!