Why can't switch on my phone?

'''i bought a Sony Xperia T2 Smart phone before one month

today while listening to music the phone suddenly switched off - it was charged - then i tried to re- switch it on but it didn't work

tried to open it using the power button and the up volume button or using the "OFF" button - beside the SIM card - but also didn't work

i concceted to a charger it gives me the red light - means it charging !!!!! - connected to a laptop , the laptop can see it !

i can't understand what happened and what can i do ! '''