Headphones aren't detected on my PC

Because neither the 3.5 mm jack nor USB headphones appear, first separate a headset fault from a Windows detection problem. Test the same headphones on another device, then test one known-good USB audio device on this PC. In Windows, run the Audio troubleshooter from Get Help, open Settings > System > Sound > All sound devices, and enable the device if it is disabled. In Device Manager, check Audio inputs and outputs, Sound, video and game controllers, and Universal Serial Bus controllers for errors. Install Windows and optional audio or USB driver updates, then restart. If absent, uninstall the affected device in Device Manager, then restart so Windows redetects it. For the analog jack, verify whether the laptop requires a four-pole headset plug or adapter. Install the model-specific audio driver from the PC manufacturer. If known-good devices still never enumerate, the jack, USB controller, or motherboard needs hardware service.