Have you made sure your computer is able to play sound?
Are your speakers turned on and sound volume turned up?
Audio & Video preferences
Go to Edit > Preferences - Click the Audio & Video tab - Turn on Play Streaming Music When Available - Click OK
Locate the music controller at the bottom of the screen.
If your Audio & Video preferences have been set correctly and the buttons on the music controller are still dark, it means that no music stream is currently available for this parcel of land.
Locate the music controller - Click the Play button - Change the music's volume by clicking the "up" arrow next to the master volume slider to reveal the volume control panel. Change the Music volume slider to change only the volume of streaming audio.
Increase Maximum Bandwidth
Go to Edit menu > Preferences -Click the Network tab - Slide the Maximum Bandwidth slider to the right - Click OK - Click the Play button on the music controller.
Music is still not playing!
Music streams do not pass through Second Life's servers. If a music stream fails to play, there may be a connection problem between your computer and the music stream's server. The format of the music stream, bandwidth constraints and location can also prevent your computer from playing music. Because of this, it is possible that other Residents can hear a music stream while you can't!
Try another music stream
To change the music stream, you need to either own the land or have appropriate group abilities on group-owned land. Stand on the parcel of land Go to World > About Land... Click the Media tab Enter a new Music URL Press Enter