This is unfortunately a common problem with the Memory compartment on certain Dell, HP and Lenovo model laptops. This problem is caused by how you handle your laptop over the years. If you hold your laptop with 2 hands (when closed on left and right hand sides) or when open (sam way) this problem will not emerge.
If you do (as I did) by handling it like a regular school notebook (you grab it on one end 1 handed, etc) after time, the pressure you're putting on the area harms the internal components of the laptop.
Motherboard is screwed to the outer plastic, so any bending (no matter how small) is also slightly bending the motherboard inside.
The RAM could be faulty, but also the socket (on the motherboard side) can also be faulty. I changed my RAM after 2 yrs, then after another 1 1/2 yrs, I got the same problem as all of you.
Handle your laptops with 2 hands and it will help prevent further issues down the road. :)