HP have not done a good job at making their vista driver installer work well in Windows 7/8.
But the actual drivers work fine. Install them as follows.
If you just want to install the scan/print drivers alone without all HP's tools, I recommend icopy scan software: http://icopy.sourceforge.net/
* Plug the printer into your USB port
* Wait for windows to detect and try to install the drivers. Printer drivers may work but scan drivers will fail
* Press windows key and type "device manager" into the search. Press enter.
* right-click the HP scan devices that show problems and select "Update Driver Software"
* select "Browse my computer for driver software"
* enter the path to the folder you unzipped above
* done. You have scan capability!