Problems keep getting worse

Ok, so recently I've been having issues with frame rate drops on BF4 despite running on low graphics and a lower resolution than my PC can put out. I can get a good 110 frames with the way I have it, but it will drop down to 70, and then to as low as 35 or 25 for no reason at all. So I looked up how to fix it, and found the easiest way was to clean boot my PC. I did so, and it worked! I joined onto a server and my PC was running at the 110 fps it should've, with no issues, and I even brought up my resolution back up to my monitor's max and could get ~100-105 fps. Then I got kicked by punk buster, and because I had been on that server before, I knew something was wrong. So I looked up how to fix PB, did what i found I had to do (don't remember exactly what) and got back on. Everything seemed fine, and then my frame rate dropped as it did before. I then also tried to clean boot again, and now BF4 won't load at all and opening it just brings me back to origin. I don't understand? Not to mention the fact that before all this, I also had a problem along side my frame rate where whenever I get disconnected from a server due to my unstable internet connection, BF4 would crash immediately upon joining that server. It would also do that at random if I tried to join a server I had never joined yet. I don't know how to fix that, but honestly I'd like to fix everything else first so I can just play the game.