trouble with some of the keys of the keyboard

i have a serious problem with my laptop keyboard. even though i was using an external keyboard my dell keyboard is creating problems.

it started with 2 keys(H & G) stopped working. but it used to work sometimes till recent time. now it has completely stopped.

the latest issue with the keyboard is that the shift key applies by itself without me applying it. it stays for a while and then goes and again repeats the same. still now i am holding my capslock key in order to make the shift key inactive. if i leave the capslock key, then the shift key again applies by itself. now i am typing using my external keyboard. please help. hope u reply soon.