HP K8600 Intallation Fatal Error

Ok... this one sounds a bit backwards, but have solved other issues like this:

Try uninstalling the HP software itself, and put the installation disk aside... power down your computer, plug in the printer, and reboot. Allow windows to discover the "new hardware" and INSTEAD of using the installation disk, have Vista locate the best driver (online if you can do it). Once you can get the printer to print with basic function, create a restore point in System restore (so you won't have to go through the initial driver install again if a crash occurs later), and THEN try and install the components you want from the installation disk. Again, it sounds backwards, but many manufacturers have had significant issues with Vista for stranger things. You may not even want all the "extras" HP includes with it's software (like online ink purchasing, photo editing, etc) but at least you can get the printer functioning!

Hope this helps!

-- RT