The red flashing light for a lot of people is the power supply going bad. You could try completely resetting the tv to see if it helps. It's the first thing the person at Samsung had me do. First, unplug the tv and then hold in the power button on the tv itself soon after for about 20 seconds. Leave it unplugged for about 5 minutes then plug it back in. The light started flashing on mine before it died completely and it was the power supply gone bad. It happens a lot on the these models. If you're still in warranty the sooner you call the better off you'll be. Note to anyone reading this. Always keep receipts for big ticket items for at least 6 months past the date the warranty is set to expire.
I downloaded the latest firmware from the samsung site and extracted the files to my usb stick. It was installing and said update completed, but now the tv doesn't turn on anymore... All I hear is clicking sounds like its trying to turn on and the red light on the lower left keeps blinking. Anyone know a way to un-brick it? It is a LN52A750.