New 3DS issues/backplate not coming off

I dropped my new 3ds (not the XL) while trying to climb a tree and it won't turn on UNLESS I plug in the charging cord, then it works fine. I've been thinking for a while, maybe the battery came loose. I got one of the screws to come off but the right screw isn't budging. Any way to fix this?

Is the screw stripped? If that's the case, it may be more difficult to take off. If not, the New 3DS as well as its XL variant really hold onto the plastic casing of the 3DS tight. You have to insert the end of your 3DS Stylus (Side that is visible when inserted into the stylus holder, not the touchpad part) into the notch on either side to lift it out.

My Left and Right Buttons on my 3DS never work anymore, so I got ambitious and decided to try and fix the buttons myself.
I got the backplate off, took off the battery.... Then i couldnt unscrew the next set of screws. nearly impossible without an electric drill to do the job. I was very frustrated and tried for the past hour to take it off with a regular screwdriver, no luck. Decided to go with my mom to her shop (its a collectible show type of place) and right across it is a video game shop (sells pratically every game in the entire world) and the guy that repaired consoles and other devices said it would cost 40$ to replace both buttons. My mom said maybe another time.... (Curse those Mario Kart 7 Drifts...)