Why would a red light be flashing instead of powering on?

Possible TCon board issue but check Pico fuse on Power Supply. Fuse is located near top left closer to connector plug . Fuse is marked as L7.
If faulty, replace ONLY with the correct value and type of fuse.

The flashing light red power light should only stay while the fan cool down for about 1 minute after a power off (remember to always wait before unplugging the TV so the lamp can cool down with the fan). Does that flashing start right away after plugging back the TV after an hour of letting it without AC power.

The red light should flash no longer than 10 sec. This prepare the light to be turned on. If all is OK the green should stay (no longer flashing) and the sound and picture come on.

As for the lamp flashing, i bet it's only 1 time each 5 sec? Or do it group many rapid flash each 5 sec?

Things that can be wrong:
-the fan lamp

-the lamp is not proprely inserted (wait an hour before manipulating it to be sure it cooled down, and use glove to not put body oil on it).

-Lamps is defective and is not operating properly so you can't get to the usual on screen message that recommend to change the lamp.

my 42 inch phillips, i turn it on green light comes on for 10 sec then red light comes on and flashes 4 times then stops for 5 sec then repeats.

this happens when the ps3 has overheated-try removing the hard drive and replacing then give the console a hoover out.....if this doesnt work try holding the power button on for 5 sec....if this doesnt work its back to sony im affraid

Please intimate exact model of your Sony TV to find out reason of no power up.

Thats the error for lamp driver error. Which means the Ballast is most likely defective. You can get the replacement ballast for your model at the following link which comes with installation instructions.
http://servicemanuals.vstore.ca/product_info.php/pName/kdfe42a10-ballast-assembly/cName/sony-parts

Power supply is bad

how many times does it blink pause then blink again?

i also have the same problem with the flashing green light for a while then a different red light starts blinking on and off around 5 times....and i replaced my burnt bulb with a new one...still no picture.

Push the light - it will flash red after a few seconds -then turn green.

The answer above on this page was correct