laptop is conntected to tv with hdmi then audio cables to receiver but no sound how do I fix this.

laptop is conntected to tv with hdmi then audio cables to the auxillory port on receiver but no sound how do I fix this. I have an older pioneer receiver with no HDMI ports. I had this working last month and for some reason it just stopped and now I cant get it working again. This is how I watch movies through itunes. I can get sound through the tc just fine but it sounds much better using the reciever and surround sound......Help