For windows vista here: http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?softwareitem=ob-55206-1&lc=en&cc=us&dlc=en&product=3446847&os=2100&lang=en
Added: HP says that it's plug and play with WinXP SP2 this is a list of MS supported bluetooth drivers is yours on it, and is it SP2? : http://support.microsoft.com/kb/841803