Dell Inspiron 15 3521 won't start, it is beeping continously (not 4 not 7 beeps) with intervals and by luck sometime it boots, no dell icon nothing black screen, Please help this is my first experience with dell, before I used Hp its quite better !

It is beeping continously (not 4 not 7 beeps) with intervals and by luck sometime it boots, no dell icon nothing black screen, Please help this is my first experience with dell, before I used Hp its quite better !