How do I open .part files?

I downloaded a printer driver package from HP. Part of getting the right package was telling HP which OS I was running it on. (10.8.5) Despite this, it won't open. The message I get says to choose an app to open this .part file with, but none of my apps seem to be the right one. I search regarding .part files, and found old archives about OS 7! So what app opens a .part file?