Things to try when your laptop is not recognizing an external microphone:

1. Check the connection: Make sure your microphone is securely connected to the 3.5 mm audio jack on your laptop.
2. Check the microphone settings in Voice Recorder: You can adjust microphone settings such as the input level and boost, so make sure the settings are correctly configured.
3. Try a different microphone: Some external microphones are not compatible with your laptop. Try using a different microphone to ensure that your current microphone is compatible.