The main board of this Vizio is known to fail after some use.
Its number is CBPF9D1KZ4 and as you will see it is hard to find, unless you want to pay $250 or so, which doesn't make any sense, at least to me.
Another common failure in those is the T-CON board, but from the sound of it the problem you have is in the main board.
Here's what I'd do if I were you: post a local ad on Craigslist, sell it to the highest bidder and use the money towards puchasing a new TV.
Not sure it's what you want to hear, but it's what I tell some customers and thus losing business that I couldn't have had anyway because it's insanely expensive and prone to more failures anyway.
If it helps you please vote for me - it helps me in turn :-)
www.coppelltvrepair.com