My friends is using windows 8.1 and he has a webcam. He says it is working very well even without installing drivers.

Webcam is A4tech - PK-331F.

I asked for this webcam for use.

I plugged that that webcam and windows detected it and installed drivers automatically. Then I opened Skype for checking webcam. I got massage on top of Skype that "your webcam has microphone" when I clicked over it, it directed me to sound settings where I microphone of webcam was working. I went to videos settings but webcam wasn't listed their.

As you can see in image. Webcam is listed in device manager but isn't listed in Skype.

I am also using windows 7 professional. Any idea why it is happening?