P2418HZ, Camera, Microphone not working, #3

my mic isn't working?

* What specific PC model?
- If a Desktop PC, what video card? What video out ports are on the video card?
- If a Laptop PC, what video out ports are on the Laptop?
* Explain in detail how the P2418HZ is connecting to the PC using all cables and ports
* What operating system?
DELL-Admin