That looks like a very nice little dedicated scanner. I did a Google on
it and came up with this imagingresource review:
http://www.imaging-resource.com/PRODS/HPS20/S20A.HTM
which contains the following at the end of the review:
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Other Software for the PhotoSmart
Thanks to its low price and the large numbers of units that have been
sold, there is actually third-party software available for the HP
PhotoSmart Scanner! We did a very limited evaluation of Ed Hamrick's
VueScan program, about which we've generally heard very favorable
comments on the rec.photo.digital newsgroup. As of this writing, it's
available as a freeware demo, with a 15-day time limit: After that,
you'll need to purchase Ed's companion VuePrint program for $40, the
registration for which includes a license for VueScan. (VuePrint is an
excellent utility for printing multiple images on a page.) Ed's
original VueSmart scanning application offered many extensions beyond
the capabilities of the HP software, and his new version has both
expanded features, and full support for the S20 version of the
PhotoSmart scanner.
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I've seen a number of references to this Vuescan utility here and it is
said to work fine under VISTA so your simplest solution would be to
download and try it.
If you do this make sure you uninstall all the HP software for the
scanner that you may have installed and do this through Add/Remove
Programs; also delete any icon that may appear under Control Panel /
Printers and Scanners. Disconnect the USB cable from the PC, not just
from the scanner and reboot.
Then proceed to install the software without the scanner cable
connected to the PC and only connect up when told to by the software
installation or after [Finish].
You could also try doing what I did with an even older HP SJ5P flatabed
scanner and that is to do a clean installation of the software using
Compatibility mode and Run as Administrator. To do this locate the
startup file for installing the software -- might be setup.exe or
autorun.exe -- right mouse click on it and select Compatibility. The
set it to an earlier version of Windows (you said W2000 worked?) and
check the box for Run as Administrator.
That worked for me when I installed the even older Deskscan 2.9
software for my SJ5P setting compatibility in that case to XP with SP2.
Good luck!