Hello, My name is ***** ***** I'll be assisting you. I'm sorry you're having problems.
Unfortunately no- there is not a simple reset feature beyond the unplugging and holding the power key procedure which you've already done. The set is shutting itself back into standby, due to a hardware failure internally. This is the self-protect mode built into these TV's to prevent fire/damage when a component has given up. If you're looking to repair this yourself, the most common cause of this issue is the power supply board- which can be purchased and replaced yourself if you'd like to go that route (let me know and I will hunt for a source for the part).
Alternatively, if this is not something you're comfortable with, a shop will typically charge close to $175 parts and labor for this fix, and is generally not cost effective as the set can be replaced for about the same cost with a brand new LED TV. However if you'd like to inquire about repairs, or seek a 2nd opinion you can use the link below to locate a shop in your area:
Again, if you're a DIY type- let me know and I will search for that part.
Other than that, I'm sorry for the bad news here and wish there were a quick fix.
If you need further assistance let me know. Before you go, PLEASE DO click at least a 3 STAR RATING, at the top of your screen. That is how I am credited for my efforts by the site. You can follow up any time as needed at no additional cost.