HELP! Screen is black on boot but boots

[TheSeaps]

Hello guys! So I built my first PC 2 weeks ago (YAY ME!), and now I'm having a problem. When I boot up the computer, there is a black screen with the letters "B4" in the corner. It stays this way for about 3 minutes and then boots into the OS. My motherboard is a MSI 970a-g46.
P.S. I can't go into the BIOS during the black screen.
P.P.S. I can upload a video if it helps.

Hope someone can help me

 

[TheSeaps]

Nobody ?

 

[BreadWhistle]

Sounds like maybe a problem with the video card. Try maybe using a different connector, say DVI or VGA. My computer did that when I tried to hook it up with an HDMI cable, but I never did get an error code....