My mother, myself, and my sister all have the same model of Inspiron 15 3552. Mine is upgraded to 8G ram with a Samsung SSD, my mothers is upgraded to 8G ram with a corsair SSD, and my sister's is stock (4G with 500G HDD).
All of our laptops have this weird intermittent keyboard problem that I've been trying to troubleshoot for a while now. Whenever we close the lid on our laptops and open them later, the keyboard about 50% will not work. It acts as if it's not plugged in. We have to reboot to get the keyboard working again.
I've tried to disable the keyboard driver going to sleep under power management, updated the BIOS to latest version, all are on Windows 1903 with latest patches.
One weird quirk is that sometimes if the keyboard does work, pressing the capslock key will 'lock' it on and the keyboard will stop working.