Philips 42" Model # is 42PF7320A TV Yr. 2005

Most likely the TV has a power supply related problem. The most common thing to go out is the circuit board that supply power to the screen. Commonly called a Backlight Inverter Board.
But, I can't say it's 100% the problem because I can't actually look at the tv over the internet.

If you have some electronic experience, if you can find and purchase a Service Manual over the internet; It will help you diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you red light flashing codes, circuit diagrams, test points, and part# lists. Usually, cost under $20. And most cases the new part cost less than $15.

I hope I shed some light on the subject for you.