macbook pro deleting letters as i type.

not all the time or I wouldn't be able to type this. in the search bar i will type one letter, it immediately becomes shaded blue, the next letter i type deletes it. have restored all defaults for keyboard and track pad. cursor was also fading to the right and randomly opening files on my desktop. restarting seems to help, but not for long. any similar experiences or suggestions? i really appreciate it.