Alright, if doing a hard reset, pulling the sync button back a lil bit doesn’t work then I have a solution ( it worked for me) lets begin.
# open your xbox shell ( Follow this: https://youtu.be/bF1V1QiB17c tutorial up to 5:35
# Reseat the ribbon cable (remove it then reinstall it — i found this video extremely useful https://youtu.be/ghcWusCrh30.
# close your xbox shell
# '''Just a tip - before closing your xbox shell test that the power button, eject disk and sync are working'''. https://youtu.be/bF1V1QiB17c Follow this guy from around 40:00 onwards ( he also reinstalls the ribbon cable here I just thought if the other video was not proving useful you can try his ‘method’ or style.