Also you must install the software before the USB cable, if that is
what it uses, is plugged into the PC and only plug it in when the
installation procedure tells you to or when you reach Finish.
Make sure you disconnect the printer cable from the PC then delete any
icons in Control Panel / Printers and uninstall any of the HP Printer
software that appears in Control Panel / Remove Programs.
Then reboot and start again as indicated.
Please answer the following questions:
What version of VISTA are you using?
Are you using a CD that came with the printer to install it and if so
does it specifically say it is OK for VISTA?
What model of HP AIO printer is it -- if you would have said at the
beginning I could check for VISTA software.