CPU and DDRAM Red Lights

What are your components?

Is the system POSTing/booting or is it just powering on and remaining at a black
screen?
If it's not POSTing, is it a new build or was it previously working?
It's hard to help with no idea what is going on, when the system was built, has it
ever worked correctly etc.

If it's a new build, make sure your RAM is in slots A2 and B2 and that your 8pin
CPU power is connected to the board, that is a 4+4 connector from the PSU not the
6+2 PCIe power connector for GPUs.

Great, thanks for the extra info.

So, the 12600k should be supported on all BIOS versions so an incompatible BIOS
shouldn't be the issue. DRAM and CPU lights being lit and staying lit typically means
either the CPU isn't supported (needs a newer BIOS), RAM not detected/compatible
or a dead CPU.

Make sure the RAM is properly seated, it can be a very tight fit on new boards
sometimes. If that isn't the issue, try clearing CMOS and pulling the battery
with the system disconnected from power. Be sure to press and hold the power switch
for 5 seconds or so to discharge the PSU and board caps and leave it like that
for 10 mins. If that still doesn't work then it may be worth looking into a CPU
RMA. If you search the forums here the vast majority of people with this issue,
it ended up being a DOA CPU. Hopefully that isn't the case.

Let us know how you get on and good luck

I have another system with DDR4 RAM I'm going to try pulling the Ram from my other system as a last resort, if that doesn't work I'm going to get a different MB or CPU.

Of all the systems I built, I've never had a bad processor, both Intel and AMD, but I've had bad motherboards. So my money is on a bad Motherboard.