It took HP many months after Windows Vista is official release to get a beta sound driver for Conexant Waikiki chipset to work. If anyone looks for it, just check this forum -> http://forum.notebookreview.com/announcement.php?f=3&a=15

To check if you have Conexant Waikiki or Venice chipset. Check hardware ID in device manager. If it shows DEV_5047, then, you got Waikiki chipset, if it's DEV_5045, then, you got Venice chipset.

Right now, the driver provided on HP website is intended for Venice Chipset only. To get a beta driver for Waikiki chipset from HP, e-mail to Anna at the following E-mail Address : hp_total_care@hp.com

Source : http://forum.notebookreview.com/announcement.php?f=3&a=15 , http://forum.notebookreview.com/showthread.php?t=109066