I lost my HP Officejet 4500's ability to maintain printer

Sometime after plugging in my Mac Pro to my Officejet 4500, I lost the "maintain printer" function. As a matter of fact, even after downloading the only printer driver/software I can find at HP for this OS 10.6.8, the HP Utility shows up in the HP folder as a 4-KB Alias instead of an application. I've installed the software three times, and always with the same result. I did not uninstall the HP printer software first because I cannot find my original disk and was afraid of the risk of completely disabling my ability to print & scan. Everything works fine except I do not have a working application called HP Utility anymore--just that 4KB Alias. When I search my hard drive-nothing shows up for it anywhere.