Hi andrew100, sorry to hear that you are having issues with the audio driver working with Windows 8.1. Please click on the link that I have provided to get to a updated driver that I think will resolve the issue for you. http://h20565.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/swdDetails/?swItem=vc-107611-1&a
If this does NOT resolve the issue, please let me know and I will be happy to offer additional assistance.
Thank you.