Use laptop microphone when headset is plugged in, not use headset mic

I have a Razer Kraken Pro headset with a microphone, but want to be able to use the internal laptop microphone when I have the headset plugged in.

When I unplug my headset, the internal microphone works; if the headset is plugged in, the headset's microphone works.

I've read about other examples, but those have been about where a user has two devices in use at all times. One for internal microphone and one for headset's microphone. I have only one for both.

The main reason being that it seems my friend can hear everything I do in Skype calls and it's a bother. It's mainly because my headphones are really strong and close to the microphone.

My microphone settings are setup as so (in Hebrew):

My laptop is a Dell Inspiron 3721 (if it matters, i7 CPU, 8GB RAM and AMD GPU), using Windows 8.1 64-bit.

The headset has an "analog 3.5mm combined jack (headphone and mic)" and my laptop also has a combined jack connection, so it works great but I can't choose or select to connect only my headphones or only my mic.

I did have a splitter to connect to the combined jack connection but I lost it.

Any ideas?

Maybe the individual application will let you select which speaker/headphone and which microphone you wish to use separately. I've seen Audacity do this and I think Skype will as well.