I need some serious help. I have Hp Pavilion a720n with pre installed Window XP Home. I installed Window XP Pro Service pack 1. After that I am unable to hear any sound media on this computer. I found this message " CD requires a sound playing capability. Please make sure that a sound card is installed and configured in your windows settings.".. I checked in control panel Sounds and Aduio Devices and Add Hardware. I saw there Aduio Codecs and Legacy Aduio Drivers and checked them and Add Hardware Wizard say these devices are working properly. Please help me to figure out this problem. All helps are welcome.