If you have compaq presario V3000 and installed XP on it, but when you plug in the headphone, both speaker and headphone produce sound, to solve this simply download this audio driver below and install it.
Conexant Audio Driver
If, it refuse to install, uninstall current driver, restart and install this driver
If you didn't hae sound from both speaker and headphone you need to install the audio driver with MS-UAA patch.
Microsoft Universal Audio Architecture Bus Driver
Version 1.00B 54MB
Restart after MS-UAA Installation. After that continue with audio installation. Do not install audio without installing MS-UAA.
Conexant High Definition Audio Driver
Version: 188.8.131.52 A 6.28M