My phone turn on and turn off only

I have HTC one 802d dual does not start only turns on and turns off does not boot or start at all. How can I solve this problem and also tell me from where can I purchase its motherboard in delhi(India). Also tell me exact motherboard name to be fitted with my htc 802d dual phone. I have tried time and again by pressing down button (for sound) as well as on/off button simultaneously. After that booting screen comes on the screen Firstly I pressed the recovery again a pop up screen came on the screen secondly I pressed wipe catch partition. Third step I pressed Wipe data/ factory reset. and finally I pressed Yes-delete all user data. Thereafter I pressed reboot system now. But all in-vain and again htc logo screen turned on and off started. My phone could not came out of stuck from bootloader and the same beaviour turn on and off started. thanks please tell me how could my phone will behave normally.