memory slot not working?

Apr 2, 2019
Hi all,
I have an eMchines E525 that has two memory slots.
All three 2GB sticks work in slot one but system will not boot when I put one in slot two.
Each stick is 2GB and system says that the motherboard will accept 4GB.
Is slot two dead or do I need to tell the motherboard something?

cheers all.