Can't Delete AVD from AVD Manager in Android Studio

Search for *.lock folders under .android folder and delete those. This should tell Android studio that the AVD is not running.

On Android studio go to: Tool > Android > AVD Manager, on the action column you can delete your avd

To stop the emulator of android that is running background in the system and to delete the emulator just go the

C:\user\username\.android\avd

delete the folder and restart the IDE. Now when you go for the emulator AVD it will ask for the new AVD to create.