PPC Did not turn on

[Dice]

ok so last night i used the phone the whole day everything was working this morning the phone did not turn on for nothing the battery was 100% full becuase when i took of the charger i checked and then i went down stairs and then when i came back the phone did not turn on it finally turned on when i plugin the charger then i disconnected the charger and the phone is still on right now any idea why that happened