Should you find that a recently re-imaged HP Probook is having sound problems, these steps should resolve the issue.
If you see a red circle with a white x next to the speaker icon in the lower right system tray, it is a good indicator that this is the correct fix for you.
You MUST be logged in with a teacher account for this to work.
1. Right click the Windows icon in the lower left of your screen and select "Device Manager".
2. Expand "Sound, Video and Game Controllers" then right click on Conexant ISST Audio and select "Update Driver".
3. Select "Search automatically for updated driver software". The computer will then download and install the driver. When finished, you will be asked to restart the device which is mandatory for the fix to work.
See Also Microphone Issue in Browsers