Contact the manufacturer and they should be able to determine the date the tv was made using the serial number, or you can try getting a copy of a receipt from the retailer, as well if you have your warranty card it may have the date of purchase and could help in getting it repaired under warranty. I hope this helps, Good Luck.

Just unplug it for like 45 seconds or more and then plug it back in, this works because vizios are more like computer monitors than televisions.