A:Answer Hi FroFro,
For the issue of your Toshiba - 55" Class LED 4K UHD Smart Fire TV, please perform the steps below:
Power Reset
1- Unplug the television from the power outlet.
2- Remove all connections from the back of the television.
3- While everything is unplugged, press and hold the "Power" button on your TV for 60 seconds.
4- Connect all devices back into the television, making sure all of them are properly connected
5- Plug the set to the power outlet, if possible, to a different power outlet or a surge protector
Toshiba Products
Lisa
http://tvna.compal-toshiba.com/us/en/