My VO37L one day would just not turn on, No picture just black screen. power works, and powers up just no picture or sound?

TV sets that have been exposed to significant surges can have multiple boards that are damaged. If the backlights are indeed firing, and you get no picture, you may have a problem with the T-Con board, assuming the main board is working properly. This is exactly why I steer people away from repairing sets that have been hit with large surges. In most cases it will be cheaper to buy new sets vs. repair them.

Power board is of course most likely problem here and I presume you found no puffed up caps on the board.

Here is teh quick start guide from Vizio - make sure your set up is correct and the inputs are in the right place. Follow this -

http://www.wigix.com/index.php/skuaccessories/downloadManual/2166516/10708/0/Vizio-LCD-Flat-Panel-TV---37-VO37LFHDTV10A-Quick-Start-Guide.pdf

Sounds like the power supply/mainboard. I have a VO32L which is the same mainboard as VO37L and it had blown caps along the aluminum heat sink.

u have bad power supply 2 bad capaciotr on power supply

I have a 32" Emerson that did the same time.
The problem with mine was one of the Power Inverter Transformer when out. It used 6 of them to power the LCD screen.
I believe yours will have more than 6 since it's a bigger screen.

The Power Inverter Board is all one piece, the best place to get one at a good price is Shopjimmy.com

the power supply for the convergence circuit is not working, check for open resistor on the primary

It is either the fluorescent backlight source for the LCD panel or its associated power supply failing.

Cable Looses signal power after 20m ... Install signal amplifier
https://youtu.be/AkiKf4G4UE0