Xperia SP wont go past boot screen(Sony logo)

the phone reboots or powers off right after the sony logo. i am using a stock ROM. I switched to stock because i thought rebooting was due to some error with cm11. now i have tried doom kernel, williams kernel to make it work somehow, it doesnt work. tried installing a stock based ROM, xperianze, and cm11 but it shows in recovery that installation/flashing was done! but then again i cannot go past sony logo, not seeing xperia logo, cm11 boot screen or anything.

is it a hardware issue or a software issue? any possible solutions?

PLEASE HELP!

by the way it does not power off when in recovery.

from xda-developers http://ift.tt/1wQ1tHn

via IFTTT