Some sound cards may have a mixer control that allows you to map the audio to the microphone input. This will be the easiest way to get sound coming from another application.
To do this, follow these steps.
1. Choose Start > Control Panel > Sounds and Audio Devices > Volume tab.
2. Within the Device Volume group, click on the Advanced button. The Playback Control dialog box displays.
3. Choose Options > Properties.
4. In the Adjust Volume for group box, enable the Recording option.
5. In the Show the following volume controls: group box, choose Stereo Mix.
6. Choose OK. The Record Control dialog box displays.
7. At the bottom of the Stereo Mix group box, enable the Select option.
8. Click on the System Close button in the top right corner to exit this dialog box.
9. You will return to the Sounds and Audio Devices dialog box. Choose OK to exit.
Now, when you record, any sound coming from your application will be recorded as well.