To record "computer sound" and "your voice" in Windows XP, enable "Stereo Mix" and "Microphone"
If there is no sound for the captured video in Windows XP, you have to enable "Stereo Mix" in Volume Control. » See more
To record your voice in Windows XP, you have to enable "Microphone" in Volume Control. » See more
To record "computer sound" and "your voice" at the same time in Windows XP, use "Secondary Sound device" and check the "Two Sound Mixing" option. » See more
To record "computer sound" and "your voice" in Windows Vista/7/8/10, choose "Win Sound(WASAPI)" and "Microphone"
To record "computer sound", choose the "Win Sound (WASAPI)" option in Primary device. If there is no sound for the captured video in Windows Vista/7/8, you have to enable "Speakers" in Sound settings. » See more
To record your voice in Windows Vista/7/8/10, you have to enable "Microphone" in the Sound settings window. » See more
To record "computer sound" and "your voice" at the same time in Windows Vista/7/8/10, use "Secondary Sound device" and check the "Two Sound Mixing" option. » See more