So I have not used my tablet in over 6 months. So I presume the battery is completely flat. When holding down the power for over a minute it just flashes White 5 times but does not turn on, have also tried the vol down and power button trick. I disconnected the battery for two minutes then plugged it back in again with the same issue. I had this posted to me from family as I moved and did not get my original charger. Am using my Samsung S7 charger which is a known charger I presume this will be fine? I have left it chargeing for over three days but still no success. Will I have to replace the battery?