That sounds like an issue that is known but continued use may prevent what could be a cheap or free repair.
Unplug it and call it in. Research BAD CAPS but do not open the set as this removes it from any hope of an one time repair option.
I can't tell if it's that but the symptom is right. Only by visiting and inspecting the set the tech can confirm.
My LCD TV is having problems turning on, it displays a greenish full screen pattern and very load noise output and is around 4 to 5 yrs old. It will take about 3 attempts to start and then will come on and be find the entire evening as long as you do not turn it off. Is this a cost effective fix considering todays tv prices?