Question Monitor black after ram upgrade

Aug 21, 2019
So I bought new ram sticks wanted to upgrade to 16gb from 8gb so I looked up my operating system, my motherboard and my power supply support the ram so I put the new sticks in I press them in tightly it clicks and I turn the pc on the fans are turning it seems to start up, keyboard lights up mouse aswell but the monitor dose not work I cant get to bios nothing (monitor is working properly) so I'm able to start it with the individual sticks I tried but when I put both in the monitor is just black.. the old ram works fine still the new one both sticks work when put solo in but when I put both new ram sticks in its black. I tried resetting cmos with the baterry... any suggestions guys? Thanks in advance

So individually new ram sticks work but when put together system dosent boot up, fans spinning etc but monitor black.
Old ram ddr3 2x4GB 1.5v 1600mhz
New ram ddr3 2x8GB 1.5v 1600mhz
Motherboard supports 2x8gb so it says in the manual.