After trying the above solution and it still does not work, I would not charge your Tablet for one day and then the next day, charge it. This usually helps for my other electronics when they should normally boot.
I have been having this problem on and off since i got this tablet when it first came out. I am getting sick of this and am about to call sony and demand a refund so i can buy a new tablet. There is so much wrong with this thing.
No fixes for this issue i have tried actually fix it. I just have to wait until it decides it wants to work. I did not spend $500 for something that doesn't work unless it wants to. I have been plagued since day 1 with this power issue and wifi barely ever working, and when it does the connection is horrid.