The problem could be that the 2600 is a GDI printer. These are also called host-based, where the Windows graphics engine does all the hard work of converting the page to dots on the page. With more intelligent printers, it's the printer that does that job. GDI printers have one advantage: they're cheap, as they need almost no intelligence.
One of their drawbacks though is that they require a different driver for just about every version of the operating system. HP's website shows drivers for Vista, but not for 2008. With more intelligent printers that might not matter (after all 2008 is a version of Vista), but with a GDI printer it may well be a killer.
I assume the drivers work fine if you install them on a Vista machine. If that is the case, I suspect that you have a useless printers until HP release 2008 drivers. They may decide not to do so.