My LG 55LV5400 Tv went of and will not come back on?How to fix this problem

LG 55LV5400-UB has a well known problem with the main board resulting in the symptom you describe or in loss of HDMI inputs or loss of sound.

it has to do with the main processor and some people recommend baking in an oven to help cure it.

We do not. There are many reasons why this is wrong, but the truth is it *could* give a short term success; it is almost certain to lead to long term problem and we have pictures and videos of boards sent to us after such attempts - usually already warped beyond repair.

Simply put, I'd say there is 99% chance you need your main board serviced or replaced.

here are two links to help with each option:

Repair:
http://www.coppelltvrepair.com/p/1632/ebt61521404-61521404-main-board-repair-service-from-lg-55lv5400-ubausylhr-led-tv

Replacement:
http://www.coppelltvrepair.com/p/1634/lg-55lv5400-ub-main-board-ebt61521404-61521404-serviced-tested-50-credit-for-old-dud