@mark08 Not exactly sure what symptoms all of this "glitching, freezing and rebooting" include. Since "used an external keyboard there's no issues and it works perfectly" I would suggest that your computer has issues with the keyboard or the keyboard connector. Time to disassemble it and to inspect those things. I would even consider a keyboard replacement [guide|126830]
Now, should you find anything odd looking, torn or dislodged, post an image of that with your QUESTION. That way we can see what you see and help you as much as we can. [guide|21499]