1st things 1st. Do you have music on your M$ dashboard? You know, in the memory part?
Anyways, if you DO (and Im assuming that you ya do!!) press the "Y" button, then go down the the "Configure" selection. Pres the "A" button to go into it. Once there, go down to the "Music&Sound" selection and press the "A" button. Once you have done this, Make sure The settings are as followed::
Enable Music Yes
Music During Video Yes
Random Music Yes
Global Music Yes
Preview Audio No (you can say yes if you want, I think its not needed)
Menu Sounds Skin Defined
Music Volume 10 (You can change this too, I like it loud...lol)
Once you have done all of this, go ahead and press the "B" button twice and select "Reset Menu Cache" selection, then hit reboot (right under reset menu cache). Once it loads, it should have music!!!! If it dosent, then you will have to check out your music folder and see if its still there....Id use XBOXST just cus its so much easier. Good luck, hope this helped you!!!!