What box do you have as I'm assuming you mean a box and not a smart TV.
How is it connected to the router? Direct or are you using power line plugs?
If the latter are the lights on and are the plugged into the wall sockets and not an extension lead? This can affect the signal.
If you look at the power lines, there should be a pinhole reset. When plugged in try resetting both of these and re-pair them.
You could also try a reset to the box by holding the power button for around 10 seconds until the box restarts (I'm assuming you have a YouView box).
If it's a smart TV can you not connect via WiFi? This might be an option now you have fast broadband.
Let us know how you get on.
Please remember to mark Solved Posts with Best Answer. Doing so helps other customers and saves TalkTalk's Support Team time by only looking at unsolved topics. Thanks, Steve (a fellow customer).
