Try removing your gpu and ram but take only 1 out at a time andd checcck after each item taken out . This happend to me and it turn out to be the GPU had failed.
Just install the drive inside the case all this so you dont have to install it lol sry i just find it silly as it take pluging in 2 plus job done i built an whole gaming pc yesterday if you go to youtube you see just how easy it is..