NOT GIVING APPROPRIATE HARDWARE IN WARRANTY PERIOD

SIR I HAVE PURCHASED A LENOVO LAPTOP (MODEL IDEAPAD Z570 S/N0.-WB02627049). I HAVE PURCHASED THIS LAPTOP ON 21/09/2011. FROM THIS PURCHASE THEY GIVE THREE YEAR WARRANTY PERIOD. BUT IN LAST THREE MONTH MY LAPTOP DEAD FOUR TIMES . FROM THIS TIME ONE WEEK AGO AGAIN GIVE FOR REPAIRING . AFTER REPAIRING AGAIN THERE IS DIFFICULTY COMES . THERE IS INTERNAL HARDWARE PTOBLEM WHICH SHUT DOWN THE LAPTOP AUTOMATICALLY. SIR I AM A STUDENT . I HAVE MANY WORK /PROJECT TO DO ON LAPTOP.PLEASE SIR TAKE CARE OF IT. BECAUSE AFTER ONE MONTH MY WARRANTY PEROD IS EXPIRED . THAT IS WHY THEY DID NOT GIVE PROPER SOLUTION FOR THIS.