I picked up a stick of memory tonight to max out at 16GB supported by the motherboard.
I already had a stick of 8GB which has been working well.
This is the motherboard: https://www.newegg.com/Product/Product.aspx?Item=9SIAGSC95H7935
And this is the memory I purchased tonight: https://www.frys.com/product/8368167?site=sr:SEARCH:MAIN_RSLT_PG
After the installation, the system does not detect it. I checked in BIOS, and the story is the same there.
Could someone tell me why this may be? Are these units compatible? If not, what makes them incompatible?
Edit: This morning I took out both memory sticks and used compressed air to clean the slots in the motherboard. After that, I was able to get the new memory stick to work by itself. Then, I added the old one. They both worked.
Hence, it appears that the problem may have been related to dust or misalignment during the installation. Thanks for you help!