Hi. I'm running XP Pro. I uninstalled everything, reinstalled, and uninstalled again. I found a different driver on HP and tried it. This may really be a problem in the hardware. What happens when I try to install the printer is it can't find the specific printer, it looks for a very generic HP OfficeJet, and even tho I know it's a 5510, it just doesn't recognize that or even acknowledge that the HP OfficeJet 5510 is in the software or drivers. I guess I have no option but to pay the shipping and return it for a replacement, it is under manufacturers warranty, so if there is a problem with the hardware itself, perhaps a new one will resolve it. I can see no other reason for this puppy to not install. I appreciate your replies. There is an amazing amount of information in this forum - I'm sure I'll use it a lot. Debbie.