Ok folks I know i just posted this but i have found the answer
As you have disabled the built-in Microphone, first lets try to set the Microphone as a Default Device and enable the same.
Perform the task mentioned below to set Microphone as default device and then enable it.
1. Go to Start and click on control Panel.
2. Click in Sound, then a new window will open up.
3. In the new windows click on the tab "Recording” and right click in the window and click on Show Disabled devices.
4. Now check if the microphone is listed there and highlight the microphone and click on "Set as Default" device.