Why is my laptop beeping during boot after repair, screen black

I will send you 20$ on PayPal if Your answer actually works

So I decided to clean the heating fan on my laptop after it was making noise (hp G7-1167x). After about 3-4 hours I disassembled, cleaned, and reassembled it. It was a pain in the ass (first time ever working on a computer). However when I turned it on, the computer powers on, beeps for a minute or less, and the screen is black, the caps lop button flashes too. The only things I can really think of is

- I didn't put electrical tape that I took off on the connectors. though this doesn't explain the beeping, or why the screen is black, unless I was supposed to put it on the screen LCD connector maybe.

-a couple of the Ribbons had a line you line up and slide into a bracket and close it. I lined them up as best as I could, but a couple would stay just a little bit outside the bracket without going in, it was impossible to push them any further in.

-I had trouble putting the ram (I think it's the ram, it's right by the Card, rectangular piece) I'm not sure I put it back in right. Could this have caused it?

-I somehow damaged the computer possibly. Didn't have tools.I had a crappy philip screwdriver and no plastic pry tools. I know not to use metal on connectors even if it's turned off, so I avoided it as best as I could but a couple t imes I did take out connector with a metal pry tool. I was very careful and took out the battery first.

-there was a small piece I broke on the top left, so I took it out and a metal plate by the LCD it was screwed into, because it wouldn't fully close the housing since it was broken. Though I don't see how this affect it. I'm pretty positive I didn't damage the LCD, I didn't really touch if, and there's no likes or anything it's all black.

could I have damaged a backlight?