I had my P1100 colour inkjet printer for over 4 years; working perfectly under XP-Pro.
After installing Windows 7 (dual boot), the P1100 printer could not install.
HP's web site stated that no drivers
would be available. As there were no Vista drivers either, I thought I had to scrap the printer.
Then I had a go of systematically installing printers from the list (Control panel\System\Device Manager etc.)
Eventually I came to HP DeskJet 970Cse and its driver
The Testpage printed ok and so does everything else, including Duplex printing.
Moral - think outside the box, don't give up
I hope this may work for other printers, where no Vista or Windows 7 driver is available.