Oshiba satellite C50-B some keys not working

Hello,
hi I have a problem with the keyboard on my laptop, my laptop is Toshiba satellite C50-B,
well anyways some of the key on my keyboard is not working but if I use a USB keyboard its working fine all of the keys are working. but if I use the keyboard on my laptop some of the letters are not working at all..
the keys that are not working on my laptop keyboard are F9,9,O,L and . I'm using my USB keyboard right now, I already tried some solution on the internet like