Try to reset it by pushing power key and volume at same time for 10 sec then put it on charger repeat if don't power up within 5 min. If it don't come back on after 3 or 4 times with this method I would maybe check the battery then the charging port last option would be your motherboard.the parts for these tabs are cheap compared to other tabs, it's the labor that costs. Good luck.
This is the third time my tab has done this. Try plugging it in to charge and leave it for 10 min take it off charger and push power and volume at same time for 10 sec the computer guy said I would only need to do that once but I had to do it 3 times and put it back on chargerit should turn on within 5min. If it don't repeat this a couple times it took 3 try for mine the first time it happened ,the second time only once. I'm back here looking for answers again this is the third time. I'm about ready to give up on this tab. I hope it works for you.