I have a Lenovo Flex 15 that was purchased last November. It was working fine and then one day it failed to turn on. All I get in the battery light with flash three times in amber and then nothing. I have tried the options noted on the site to reset the laptop - e.g. taking the battery and unplugging the AC adapter and holding the power button for 30 sec. It won't turn on even when plugged in to the AC adapter. I replaced the AC adapter and not change. Should I replace the battery?