I have both Windows 7 64-Bit and XP Pro on a wireless network with my HP Officejet Pro 8500 A910. The HP was new in 2010. Today I had to insert a new yellow cartridge. The Printer Assistant that comes with this always indicated that the printheads were good. However, with the mix of new and old cartridges, the print was not accurate. Today, after doing the routine maintenance tasks, I thought the new yellow cartridge would make a great difference. I could have lived with the cleaning and calibrations results; but the alignment fails. No yellow prints out against the white paper I wasted tonight; but the ink levels show all three color cartridges down considerably and evenly even though yellow on paper doesn't show at all and there is not much blue either. Now, it goes into alignment, which it never completes, before printing. So, instead of printing inaccurately I cannot print at all. I have three choices: 1) new printheads; 2) replace the entire unit; or 3) blow compressed air into the openings of the old printheads (probably messy). I am not happy with all these utilities that HP provides that troubleshoot these problems. What would you good folks with this all-in-one wireless printer? I think the printer listed for $299. The two printheads are about $130. After using the Printer Assistant, I used their Print and Scan Doctor, which detected a driver conflict. The newly installed driver was probably the same one I had. What a waste of time tonight!