WIA setting is automatic, so I can get by with using the HP software.
Just in case ... Try turning off WIA and rebooting and then turning it
back onto Automatic and rebooting and seeing if The VISTA Fax utility
works .....
But set a restore point before you do in case it stops HP from working.
But my experience with the freestanding HP SJ5P Scanner was that if I
turned off WIA I could install the HP Software and it would recognize
the scanner, which it did not before or else WIA jumped in and said it
could not, but that later with WIA on Automatic the HP utilities
continued to work and WIA was available for other applications.
This started back on W2K and continued through XP to VISTA but I don't
have scanning or faxing from the computer.
HP Deskscan 2.9 that I used did write Scan menu items into some
applications -- including MS WORD, Lotus WordPro and Irfanview from
memory.