Plug in the mic. Then:
1) Check Skype to make sure your mic is set to its default recording device.
2) Check Windows (Control Panel>Sound) to make sure the mic is set to the default recording device and that the Stereo Mix device is enabled.
3) If neither of those help, uninstall the Realtek drivers and let Windows reinstall the drivers itself. (Make sure you're connected to the Internet when you do this step.)
4) If it still isn't fixed, can you get another mic to see if the problem is your pink microphone port?