Theres no sound comming out of my ps3?

i got my ps3 today preowned from game an i have to use the red white and yellow leads the ones it came with and i put them into the tv wich isnt hd :( and there is a picture but there isnt eny sound i did the thing where you hold the reset button and nuffin has happend. btw i dont put the cables straight in the tv i use the scart lead it came with. is there eny way to solve this?