Rob_5 :
Try going into Control Panel and selecting SmartAudio if you have it. Go to Audio Director and choose Multi-Stream. This enables the 2-in-1 jack socket to be for both microphone and speakers. You may still have to go to Manage Audio Devices in Control Panel to select your defaults i.e. turn off the on-board laptop microphone etc.
Hope this helps someone.
Thank you so much! This has really helped me!
My laptop has a combo jack (that I thought was a headphone jack!), so I bought a USB audio adaptor. I tried plugging both the headphone and the mic of my headset into the USB adaptor, but it only recognised the headphone part. Also tried plugging headphone into USB adaptor and mic into the combo jack, same result.
I followed Rob's instructions, went into SmartAudio and chose Multi-Stream, also changed the Jack Configuration from Headphone to Headset. Now it works with the headphone line in USB adaptor and mic in the combo jack.
Thanks again!