Strange problems after replacing logic board

My sister’s school laptop went kaputz and it’s not under warranty so I decided to take a crack at it. When checking the warranty we went to the apple store and the apple genius told me that the logic board was faulty so I bought one online and did it myself and got the laptop working again, but now there are strange issues with it.

The biggest one is that the power button doesn’t work like it’s supposed to. The charging cable will be plugged in and light up yellow showing that it’s charging. I’ll push the power button and the light will change from yellow to green, then back to yellow showing that it’s getting the input but not actually starting the computer. When I disconnect the battery and plug the charger cable in the mac starts up fine though.

The second issue is that the keyboard and trackpad stop working after the login screen. The computer will boot, both the trackpad and keyboard work fine when selecting a profile and inputting the password. After being signed in however both become unresponsive. plugging in a usb mouse and keyboard works fine.

Any help with these issues would be greatly appreciated.