Connecting laptop to tv, audio problems

Hello,



i recently bought a hdmi cable for my compaq laptop to use with my tv, however i could not get audio with it so i got a basic rca audio cable this morning and that solved the problem, however now i turned my computer on and the audio has once again dissapered, i checked the sound settings and it says my tv is the source for sound and that it is working but i still get nothing, any help would be much appreciated