Vizio M75 Half Screen Flickering , now not turning on again

4 Year Old Vizio M75-C1 TV is not turning on again.

Bought TV 4 Years ago, 3 Years ago i had to replace already the LED Driver Boards, because the Backlight went out.

1 Week ago i had a Half Screen of Flickering. I tried to turn it off and back on, and now it doesnt turn on again and only shows the LED-Power-Light, Screen doesnt power on.

I changed already the T-Con Board.

Please help.