|OK here it is:|
First play some music \ sound \ song using whatever program you use (ie winamp) through the computer speakers
Then go to:
Control Panel>RealTek HD Audio Manager>Speakers (tab)
In the right hand column under digital or analog (depending on your settings) you'll see your mic and headphone inputs represented by small circles. If nothing is plugged in then they should both be greyed out and unavailable. Then plug in your headphones. The headphone input should now be blacked in and available. Right click and select "Connector Retasking" You'll get a dialogue box pop up that says "The current connected device is" . Select "Headphone". Also below select "Enable auto pop up dialog when device has been plugged in". Click "OK". Now your computer speakers should cut out and your headphones should still be playing. In future each time you play sounds, adn then plug in headphones, the dialog box will appear allowing you to make the selection again. Kinda complicated I know but it worked for me. I'd be interested to hear a more simple way to accomplish the same thing????