Have you installed the proper OS version of driver/software?? 32 bit /64 bit??
From manufactuter's page, driver support is provided only upto XP. Where you got the vista drivers?http://h10025.www1.hp.com/ewfrf/wc/softwareCategory?product=61956&lc=en&cc=us&dlc=en&submit.y=0&submit.x=0&lang=en&cc=us&y=0&x=0
uninstall the software & uninstall the device from device manager & restart.
Vista should detect the printer & install the drivers automatically!