Laptop built-in Mic interferes line input

[Radivoj]

My Dell Vostro3700 Windows7/32 with IDT High  Definition Audio Chip  offers only 48kBps sampling rate on recording via Windows Direct Sound. As IDT specs say codec supports 192kBps, I installed ASIO4ALL driver, activated by my Software Defined Radio (SDR) application.
PROBLEM: even when I plug-in the cable into the laptop's mic/line-in jack, the laptop's built-in microphone is still active, so any ambient sound interferes with the line-in signals! ASIO4ALL setup box in WDM device list shows IDT High Definition Audio Codes and below it HpOut and MicIn2 as active. MuxedIN and Speaker/HP are crossed out.

Any solution?

[Oliver]

I have the same issue! Can't make the Jack Mic to work with AudioForAll and all I can record is the internal mic.