HP Scanjet 5590 buttons don't work on Windows 7 Enterprise but did work on Vista. Removed hp software, rebooted, installed HP software for the scanjet 5590, rebooted. Made sure that the Windows image Acuqisition service was started (and set to automatically start). We can't enable terminal services at this site (security won't allow it) but I saw that was one possible solution for this problem.
tried setup_full_5590_3.exe and twain.exe software for windows 7. scanning works ok but the buttons on the scanner don't work.