I don't find 10.5 support at http://h10025.www1.hp.com/ewfrf/wc/softwareList?os=219&lc=en&cc=us&dlc=en&product=57742&lang=en
Be careful when changing the OS since software and hardware can be left behind.
My older HP OfficeJet G55 printer still operates fine - if I only had a driver download for OS X 10.5.
Since installing 10.5 I had been able to use the printer up to now. I had to often run the driver download (G_731_EN.dmg) to get to the set up assistent as it easily dropped identification of the printer, but now it has gotten to the point the driver download for the last listed OS (10.4) won't even run.
I am a technophobe rather than technophile. Amy good hearted assistence out there?