Can you do us a test and put the routers power adapter on a separate power strip or wall out let with out any other devices connected? Wondering if there could be some problem with all your devices connected to one strip on one out let. It's not recommended to put T.V.s on the same circuit as other devices as t.v.'s draw more power. Also could be introducing some interferences on the power line.
I tested this, and the router still failed.
Connected to power strip A was only the router and the cable modem (Motorola SB6121).
Connected to power strip B was the tv, etc....
Anyway, I turned off power strip B, rebooted the router and cable modem, and the router still failed without power strip B ever being turned on.
If I get the time, I may try moving the router to a different location to see if anything changes. Any other ideas?