my memory not working

Pers__

Prominent
May 8, 2017
1
0
510
Hello everyone.
My computer does not recognize one of my memories.it was working properly till I once removed it and now when I install it back it's not recognized.

And idea what to do?
Main board:giga-h61-s2p
 

Nima_3

Prominent
May 9, 2017
3
0
510


My pc wasn't working well then I thought the problem was from memories.but it was from my graphic card.