Q: My MacBook Pro  won't turn on

So last night I open my computer to go on it and it was acting a little slow, like it took it a few minutes to let me use safari and when it did it was still kind of on the slow side but I could still use it. But then the screen suddenly went black and so did my keyboard but I could still hear it running. This problem had happened to me before when I first got it but I was able to fix it following the instructions online.

I turned it off, let it sit for a moment and then I turned it back on. It made the chime and it was running, the sleep button flashed and my caps lock light was on but the screen was still black. So I turned it off again let it sit for moment and then I turned it on holding down shift. Again it did the same thing. I also tried command + alt + p + r. Still no use, so I once again turned it off let it sit and turned it back on while holding shift and I pressed the comman alt thing multiple times. And then the white screen lit up with the Apple sign telling me it was loading. Once it finished it came to a dark screen and the screen lit up with a window telling me to reset my password. I did and it restarted itself and then the whole problem happened again. It wouldn't turned on, the screen is black for awhile and then the whole screen pops up and loads and then it wants to reset my password all over again and restart. This repeats itself.

Now about two months ago there was an accident. i don't usually leave my laptop on my bed in fear that it will fall off. But I got up to grab something off my desk and my dog had stretched and had pushed it off. Everything looked ok until I saw were it fell. I had a small USB in it for my mouse and it was shoved all the way into my computer. i got it out with some help but still some of it is in there and this caused it to push up and made the bottom part of my Mack open a bit. So where the bottom is and the screws are it had pushed it up. So I made sure everything was working Fine. The only thing I can't do is put USBs and headphones in and all that. I can still charge It.  everything works and it has been working fine up till now...

i Also am not sure what update it is. I have updated it but not recently.

thank you.