Every time I connect my headphones through the headphone jack in the side of my computer the sound plays through both my headphones and my computer's stereo. My computer is a Compaq nc6220 with Windows XP and I have Realtek AC97 Audio.
1. Go into "Control Panel" and then "Sounds".
2. Make sure your headphones are plugged in and then "right-click" on them in the listed items in the "Playback" tab. It should open on that tab.
3. Now you want to click "Set As Default Device".
4. Click "Apply" at the bottom of the Sound window and then click "OK".
Your speakers should then be the Default Device when the headphones are unplugged and the headphones the default device when they are plugged in.
Thanks for the advice,
Control Panel > Sound and Audio Devices > Audio tab >
Here I find the Sound playback section and the Default device selection. Although my headphones are connected the only device detected is Realtek AC97 Audio and when I select advanced and select my speaker setup as Stereo headphones and apply it does nothing.