Ram not detected problem!!!

Hello so i have all my questions answered and im ready to make a thread about this.
I have 2 8 gig ram stick 1 is 4000+ mhz and second in 3000+ mhz. I found out that you can have different frequency stick in the same mb.
Currently my computer has both memory sticks inserted but i only see 8 gigs(in windows and bios)
i tried updating bios which made my windows boot corrupt so im not risking it again for a biscuit.
My computer came already built which is a problem.
Is there anything i can do or mb second ram slot is broken?
Best Regards - Rokas

Remove the new RAM, and put the old RAM in the second slot, try to boot. This will test whether the second slot is bad.

It's still possible that second stick is bad.

You could try to boot with just the new RAM stick as an alternative.

Already did that a while ago. Well it seems that my second ram slot is bad. Thats a good thing to hear...