When I close the Laptop and reopen it, the screen never comes back on.

I just changed out the RAM (from 6GB to 16) and then an update occured and now whenever i close the Laptop, the screen never lights back up. the keyboard does and the power button looks fine, I can hear it whirring up, but the screen never comes back on unless i hold down the power until shut off and restarting the whole computer. then the screen comes on fine. What happened and what do I do?