recently upgraded my desktop from xp to windows 7 ultimate. Now the speakers are not working. They were working fine in the xp. I checked the device manager and found that High def audio device is present under the sounds, games options. I checked the status and it shows working properly. the speaker icon in the taskbar is also showing good. it detects digital audio device( s/pdif). my speaker is of philips. I checked it with a headset also, and it too does not work. but both these are working fine in my laptop! please advice ..