Operating System: Windows 98 (Note: might work with other versions of this os.)
Unzip the files to a convenient location (say C \download). Then from the START, SETTINGS, menu select PRINTERS, Add New Printer. Select "Have Disk" and then use "BROWSE" to point to the directory where you put the unzipped files. Everything should be cool from there.
P.S. After installing the printer, the unzipped files can be discarded, and only the "HPLJ3150DriverFiles.zip" may be kept as a backup if needed.