dell latitude e5450

Hi i am having a Dell latitude E5450 laptop and it was purchased on 2015. Its battery was charging only sometimes and sometimes not charging while plugging. So initially thought it is problem with charger or battery. But after taking battery out and tested the laptop , it is turning off after...

So, today i got a replacement keyboard for my dell latitude e5450 and the arrow keys (and some function keys) are not working. I have windows and ubuntu on my laptop, and i am stuck on ubuntu. Please Help! i only got $70 so please dont ask me to buy a new laptop :(