Question I need help with my first pc build

[F1edd]

The other day I began building my first computer which I finished with little hassle but after I plugged in the monitor and turned the computer on the monitor didn't regognise it. I've tried 3 different monitors and cables (all working) I've tried to clean my ram and Gpu checked my cables (all plugged in properly). All my compenents are new as of 2 days ago and seem to be working as the monitor recognised my computer for a couple of hours and when I turned it off and on again it went back to the former issue.
Here is a list of my components.
Processor=AMD Ryzen 5 3600
Motherboard=Asus Prime B450m-A updated bios
Graphics card= Radeon RX 580 Sapphire nitro+ special edition.
Power supply= Evga 500w 80+ efficiency
Hard drive= seagate 1tb
Ram= cheap ram 4gb
Cooling= 4 corsair fans
Case= corsair carpide spec-delta.
Thankyou

 

[ChevetteSCx]

I am a little unclear as to the problem.
Firstly, you did not list your primary monitor...(make, model, etc.)

When you turn the PC on, the monitor :
a.) Does not display anything - black screen;
b.) Displays only floating ''No signal'', ''No input'' or Selected Input (VGA, DVI-D, HDMI, DP, etc.)
c.) Displays garbage or something that can only be described as scrambled video?