Regarding keyboard issue

Hello sir , I purchased laptop of dell company 1years ago and now I do format one times . In my keyboard some problem are there like automatic repetation of  decimal numeric key when we unlock numeric key. and through arrow key written word become erase . Sometimes no any key work properly but when I restart the computer then key start work properly but problem of  repetitions and arrow key doesn't remove .  This problem are also there before format . please help what I do