Question System not booting + no display

Feb 24, 2020
Hi all, newbie here!

Read all the steps to try before posting here, so I hope I've not missed something. I've just finished a build that I started at the end of 2015. Here are my parts:

Gigabyte Z170X Gaming 7
Intel 6700k CPU
4x Corsair Vengeance LPX DDR4 8GB 2666Mhz
1x 2TB Western Digital Black HDD
1x Samsung m2 970 500gb SSD
Corsair H105i cooler
Gigabyte RTX 2070 Super Gaming OC
Corsair CX750M modular Power supply
All cuddled together in an NZXT Noctis 450 case

Upon booting I get the LED error 55. When looking at the mobo manual it tells me that's an memory initialisation error. I've stripped back to one chip in the first RAM slot, checked that the contacts are all clean and free of any marks. Despite part of the system being started in 2015, it's completely unused and dust free. To avoid any doubt about one faulty RAM chip, I've used every single chip separately in the first slot to check that it is still producing the same error.

I've double checked all connectors are plugged in the correct places, and I've also removed the CPU, reapplied a bit of thermal and checked if it could be that. Unfortunately, the same issue occurs, error 55 and no display at all ☹

I understand the z170x is a bit dated now, but has anyone had this issue, and has experience in resolving it? I've included a wee video just to show. All and any help is greatly appreciated, I just want this finally up and running 😃

Z170X mobo error 55