I have a Toshiba Laptop (model unnecessary) running windows 8.1. the issue is that i'm trying to use my headphones (no built in mic) in the audio jack (single hybrid audio and mic jack). The laptop has a built-in microphone, but it's disabled when i plug in my headphones (opposite of what i'm intending). so i want to plug my audio-only headphones into the hybrid jack, and still use my built in mic. any suggestions?
You can't. As you can see from the picture below, all other jack types, including headphones that do not have microphones, have left channel orientation for the end connection but the headset type combo port is designed for the end connection to be microphone. With another type of plug installed you are simply running a mono signal to each channel of the headphones and the internal mic is being disabled since it detects a connection. Since that connection is intended for the left channel of the headset, it will either do nothing or in some cases result in slight static, cracking, white noise type interference over the audio or speaker circuit.