Try connecting another signal source e.g. DVD player and check if the TV operates OK or not.
If it still has problems then check the manufacturer’s warranty statement (should have come with the TV or is in the user manual) about how to make a claim for a manufacturer’s warranty repair or replacement.
If it is OK when using a different signal source try using a different cable between the cable box and the TV or a different input (if using HDMI) to see if it is the cable box that is the cause of the problem.
If the cable box is connected to a HDMI input on the TV if possible try connecting it to a Component input (red/blue/green +red/white) or Composite input (yellow + red/white) if the box has these types of outputs and the TV has the types of inputs.
The reason for this is as your TV is a new model the HDMI inputs will most probably be HDCP compliant whereas the cable box HDMI output may not be and this can cause problems, but I may be wrong about this ;-)
If the cable box is suspect what is the make and model number of the box?