btp9001

My daughter has an Acer laptop running xp. It has a built in microphone, but we have also installed a logitech webcam with mic. The webcam and mic work fine, we've tested them. When running Skype we can record voice on the "test your system " option. However on a Skype call to another user there is picture but no sound. The laptop receives both picture and sound. Have tried changeing the Skype setting to the logitech mic but still doesnt work. Your advise appreiated.