What does the flashing yellow light on my new PS3 mean

it is the red ring of death for ps3. sorry, but your ps3 is broken or needs to cool down a bit. hope it helps. it will not work unless you get that fixed, so be sure to get it repaired. if it was a BRAND NEW ps3, call sony and complain. they might give you a free repair. other than that it'll be $131 out of your pocket to get it repaired by sony! sorry it happened. if you bought it from walmart, go up there and smack some sense into them and complain to get your money back. hope it helps you, but all i can say is you won't be playing that new ps3 unless you get it fixed!