Inspiron N4010 64-bit Windows 7 and Windows 10 do not recognize 8 GB of RAM

I bought two 4 GB chips of RAM from Crucial to upgrade my Inspiron N4010 from 4 GB RAM to 8 GB. It was Windows 7 first, then I upgraded it to Windows 10, still OS does not see full 8 GB. Each of 2 chips, installed by itself, is recognized by the system just fine, but when I put both in, it still detects 4 GB only. Any suggestions? I ran Dell diagnostic tool and it did not find anything wrong with the laptop. Prior to buying chips from Crucial, I ran their diagnostic tool and it recommended the right product for me to buy. Description of the Crucial product says it is compatible with N4010.