Keyboard not working!

Device: dell inspiron 3581

OS: windows 10

Problem: my built-in keyboard is not working! only the windows button works. it looks like maybe keyboard is locked or disabled somewhere. External keyboard works perfectly. I tried many way but failed. then I reset the pc, windows reinstalled. But still same. Also automatically opens pre boot menu every time after startup. is there any chance in boot menu. And how can i fix it