Hmm seems like it's not a driver issue as I've double checked and without Cortex running, I can record sound from the microphone jack on the PC with WinXP Sound Recorder.
I've double checked the Sound and Mixer Schemes > Conversation > Input tab, Microphone is checkmarked.
The Output tab matches the same as 'Sounds and Voice', Output tab, which I know works due to front door bell melody.
Any hints on how to troubleshoot this?