da how good is the battery backup of this Aspire 5742. i am offered a price of 31k for Aspire 5742 - Intel Core i3-370M processor (3 MB L3 cache, 2.40 GHz,DDR3 1066 MHz Ci3/Intel HM55Chipset / 4 GB DDR3 RAM / 15.6"HD-LED/ DVD Writer/ 500GB HDD LX.PTW0C.023 BT/ MultiCR / GigaLAN /WebCam/ 4 x USB...