Well, my phone has been randomly reboot and stuck on a bootloop like crazy after my niece dropped my phone. I went to a repair shop saying that maybe the motherboard damaged due to the impact and they can't repair it. Wanted to send it to Samsung Service Center but is it worth the trouble. If it cost the same or more than when I bought it (I bought the phone secondhand), I think I consider buying a new phone then.
if motherboard prob mayb it will cost d same price or more..since it can still boot, can u try enter recovery mode n flash any rom.any stable rom will do.see if it still give u bootloop n random reboot.try with flashable stock rom (there's a guide in the gen thread bout on how to flash it).if cant enter recovery mode try installing using odin..really sorry if it didnt help.atleast ill try all of this b4 sending my phone to SSC.
maybe u can call SSC(samsung service centre) n ask them how much does it cost for replacing damaged motherboard.will save your time on going there.