Keyboard and trackpad not working

This one time I started my laptop and it started searching for bluetooth mouse and keyboard, even though they are integrated. So I began using it with external peripherals and it worked. I tried to see if it was a software problem and it wasn't. So i decided to get it fixed and they now say that i would have to repair the entire logic board, which would be quite expensive. Is there a cheaper solution for just fixing the part that affects the keyboard and trackpad? Failing that, could i get some tips on modding so that that logic board doesn't go to waste?