Update to Latest OS X Upgrade to the latest version of OS X. If you are upgrading from Lion to Mountain Lion, then tere’s no need to visit a store and fetch a box, and install a bunch of discs. Just click the Mac App Store icon on your Mac. Buy OS X Mountain Lion. And your Mac does the rest. Follow this Apple guide for more info Clean System and User Caches etc....
Currently there is no a official driver available for the HP Color LaserJet 1600, however there is a simple work-around. First download and install the HP Printer Drivers v.2.12 for OS X - from Apple Support. Next install the HP Color LaserJet 1600 using the “HP Color LaserJet 2600” from the dropdown list in the config section as the driver for the HP Color LaserJet 1600. Confirmed to work for OS X Mountain Lion, OS X Lion and Mac OS X v10....