You still never said what u tried with ram, the pic showed 1 slot filled and then i said try a 2nd stick in slot 4, so 2 and 4 are populated, then if that didnt work try the other two sticks in the same slots. To rule out ram issue.
Yes what a kafullfull
Least if it was ram it has lifetime warranty usually. So can always get it changed for free if it ever defects.
I just kinda wish u didnt put the contact plate on the new mb to rule that out as a cause somehow. But ah well. First rule, build basic then test if u can get to bios ok, then finish adding stuff, test again bios, then finally finish up the cabling and install windows or whatever and enjoy.