Hi,
Try the following.
Download the IDT Audio installer on the link below and save it to your Downloads folder.
http://ftp.hp.com/pub/softpaq/sp61001-61500/sp61258.exe
When done, open windows Control Panel, open Device Manager and open up Sound, Video and Game Controllers. Right click the IDT device and select Uninstall - you should also get a prompt to remove the current driver, tick the box to allow this and then proceed with the uninstall.
When complete,download and reinstall the Chipset driver on the following link.
When this has completed, turn off the machine by holding down the Shift key as you click Shut down.
When the notebook has shut down, unplug the AC Adapter and then remove the battery. Hold down the Power button for 30 seconds. Re-insert the battery and plug in the AC Adapter.
Start the notebook and let Windows fully load - it will automatically load an audio driver, but just let this complete. Then open your Downloads folder, right click on the IDT installer and select 'Run as Administrator' to start the installation. When this has completed, right click the speaker icon in the Taskbar and select Playback Devices. Left click 'Speakers and Headphones' once to highlight it and then click the Set Default button - check if you now have audio.
Regards,
DP-K