samsung le40b620r3wqxu, i have the same problem. my tv was in warranty when the screen developed 2 lines across it, so the screen was replaced. then the pcb power was replaced shortly afterwards. now it can take a while to turn on(it just keeps doing the start up noise). and now it is turning itself off and i have to remove the power lead and replace for it to start. i also bought this from Curry's. i am led to believe that model no.s are unique to certain stores, so that you won't find one cheaper. i have friends with Samsungs that have had no problems. when it works, the quality of picture is excellent, but now i am wishing i had got something else. it would be nice if they were to admit a fault and offer a replacement. i shall be phoning them to complain, and hopefully find more comments like these to back me up.
Paul Checkley, July 2011