The reason that the RED light coming back on and the set does not start up is caused by the safety circuit cutting in to stop damage to the set due to a fault. That's the good news...
The fault could be many things, but by far the most common relates to short circuit transistors often the drive to the LOPT (Line Output Transformer) pulling to much current from the power supply.
Unless you are a technical person this is a job for a good TV repair shop...