First Build Screen Problems

we need your hardware info to help. if it an intel mb check that the 4/8 pin power plug on the edge of the mb is plugged in and you used the brass motherboard standoffs to keep the mb from shorting out. with intel mb sometime the onboard video port is the main video output on first power up. some time if the bios is old you have to boot without the gpu and one ram dimm then update the bios.