To fix the problem "No Audio Device" problem, use the audio troubleshooter on Windows 7, which is found by clicking the Sound icon in the task bar. "No Audio Device" is a message that may appear on an HP or Compaq computer with Windows 7.
It is best to restart the computer before accessing the audio troubleshooter in Windows 7. Take a look at the sound icon in the task bar. If it has an X over it, there is no sound, but if there is no X, the computer has sound, and it may be the volume.
By right-clicking on the Sound icon, a menu pops up where you can troubleshoot sound problems. Click this option, then wait for the results. The system may automatically fix the issue, but if it does not, the audio drivers may need to be reinstalled. To do this, open the Recovery Manager and choose the Hardware Driver Reinstallation option. Select the correct driver from the list, install it, and then restart the computer.
If reinstalling the audio drivers doesn't help, Microsoft System Restore may be an option. To use it, simply open the program and restore the system to a previous time when the sound worked. If this doesn't work, the only other option is to use the HP System Recovery program, which sets the system back to the original configuration.