How can i play music on my PC while the display is off?

You would just have to go into the power settings and change the settings that say something like "What my computer does when the lid is closed" and change that from Hibernate or Sleep to Turn screen off or nothing. Then when you close the lid the screen should turn off but your computer can still play music since it won't go to sleep.

Sorry for not knowing the exact terms you need to look for because I don't have Vista.

Yes having the display off uses less energy. But if you have it plugged in, the battery isn't being effected.

Set the laptop not to do anything while the Lid is closed. Play your Track then close the Lid. That's it

well there should be a display turn off on your laptop i think its fn them f something