Unfortunately, the issues you are experiencing are symptomatic of an internal hardware defect, meaning a faulty power supply or main/control board, though there are many possible failure points. This issue could be a manufacturing defect, but is also often caused by a power event (shock/surge, prolonged over/under voltage condition, etc).
This could also be the result of age related wear and tear; as a 2014 model tv, that type of failure wouldn’t be surprising for this brand. These vizio tvs are built to meet a certain price point, not for quality or longevity, and as such it is normal and expected for them to last just a few years before failing.
There is one step you can take here, both as a possible fix, as well as a diagnostic evaluation:
1) Unplug the power cord from the outlet
2) Wait at least 1 hour (60+ Minutes)
3) Press and hold the power button (on the set, not the remote) for 60 seconds
4) Keep holding power button while plugging back in, and for another 60 seconds after. When plugging back in, go directly to the wall outlet, bypassing any power strips or surge protectors.
If this reset process does not work, it would unfortunately confirm an internal hardware failure.
This is something that would require repairs to correct; if you're thinking about a do it yourself repair, you'll need to be comfortable and skilled with electronics repairs, which could include dismantling the set (removing the back panel of the tv), diagnostics testing with a multimeter, changing out boards as needed, and possibly desoldering/removing and soldering/replacing individual components.
If you’re considering repair at a local shop, you’ll find a typical repair to be around $300 for diagnostics, parts, and labor.
For a tv of this size/age however, replacement will make more sense. You can get a brand new LED tv with a fresh warranty, from a more reputable brand, in the $400 range.
Since you bought it from costco though, you should still actually be under warrnanty; even though the vizio warranty is only a year, costco doubles that and gives you a 2nd year of warranty coverage for free. So if you call the costco concierge number they can authorize service for you. Just be aware that it will likely be in the shop for awhile waiting on parts, and that even this won't be a long term fix as other parts will continue to fail. Ultimately it would probably be a good idea to still buy a new tv, and when this one is repaired you could use it in a guestroom, for the kids, etc for however long it lasts.
Depending how you’d like to proceed here, I can help with finding parts, finding a repair shop, or recommending replacement options. Just let me know.
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