Will flashing this Hard-brick or FIX my phone??

Hey all

I have a galaxy Mega and it's problem is that it won't boot until it's plugged to charger AND it boots right into download mode,..

I planned to flash a full 4 files stock ROM so will this fix my problem, or at least fail or will it make me lose IMEI or S/N??

Help plz :confused: Don't wanna risk