Sometimes, you can use newer model drivers for your old hp device. Now, if that doesn't work and If drivers can't be found for your old devices, installing on an XP Machine and printing over the network might do the trick.
Annoying as this is, it would be a solution to your problem.
I am using Vista for Standalone Gaming purposes but, as of yet, I am having a hard time getting used to the new things it brings and driver issues is one of my major pet peeves, regardless of who's fault it is.
i actually have the driver for the acer 320u, but i can assure you that it absolutely does not work with vista 32 or 64 bit flavors. my workaround: on my laptop i set up a dual boot with xp, and on my desktop, i installed virtualbox and ran xp virtualized and used the scanner in the virtualized xp environment. then i just gave up and bought a new all-in-one printer/scanner/fax.