QUESTION: My Windows 7 PC plays audio through headphones but is unable to pick up sound from them. I've got a Creative SoundBlaster X-Fi card and a Logitech USB phone/microphone. The drivers are up to date.
ANSWER: You need to initialise the microphone. Go to Control Panel, Sound and click on the Recording tab. Ensure that the microphone is set as the default device by right-clicking it and selecting 'Set as default device'.