Question 5 beeps no post or boot

[WakersQuakers]

So I have had my built system for around 6 months, it only had 16gb of RAM so I bought another 16gb stick recently. I put the stick in and the PC wouldnt boot. 5 Beeps and resets iteslf, no post nor boot. nothing. Took the RAM back out, still the same. 5 beeps. took the other dimm out, still the same. took everything out bar CPU, still the same. took the CPU out and nothing happens, just powers on for 1 second and shuts off. So I rebuild the system and it is still the same 5 beeps.

board is a gigabyte z370 aorus gaming k3

thinking it's either the CPU or board but advice would be appreciated

Help?

 

[Dark Lord of Tech]

Adding new memory is hit and miss even if identical.

 

[WakersQuakers]

Adding new memory is hit and miss even if identical.

however it still doesnt work with anything in? has the new ram somehow damaged my mobo? im trying a new CPU on monday to see if this is the problem but if not new mobo is the way i'll be going