Black screen after ram upgrade

[DrakkenWolfgang]

Hello. I am need some help with a computer I recently acquired. The laptop in question is a hp pavilion 15-p157cl.

Got this laptop from mother in law and was in essentially new condition. Had Windows 8.1 still on it, updated to Windows 10. No issue there, other than it being a little on the slow side.

I was planning to upgrade as much as possible hardware wise [ram, hdd to ssd, new thermal paste]. So i went ahead and did so. I had no issues booting before, until i swapped out ram. I know the upgrade ram i put in is compatible, but now the computer screen is not turning on. System is powering on, power light lights up solid, fan spins, and hdd is being read. Just not getting any screen image.

I have:

1] hard reset

2] removed/reseated ram/ put original ram back in

3] removed cmos battery & put back in after waiting over an hour. Also have tried a brand new battery with no luck.

4] checked cable connections for mainboard/ lcd/ etc multiple times & removed/ reseated each

5] have attempted to hook up to external monitor [laptop has hdmi/ monitor has hdmi]. Monitor detects something has been hooked up, but still have black screen on there too.]

6] have attempted to use win+b+power button to revert bios 

7] have tried to access bios. Still black screen.

So i am currently lost as to what else i can try. Also, keyboard lights for caps lock/ num lock do not turn on when pressed.

Any help or suggestions would be greatly appreciated, as I am want to get this working for my stepson to have a working computer. One more note, made sure to wear an esd cuff when working on laptop ro ensure i did not accidentally fry something lol