When I plugged my cable into the computer, the same thing happened. It was automatically installed. Then, when I plugged the cable into my Deskjet 722C printer the printer was detected and installed. I don't remember doing anything else.
The printer had already been installed on my parallel port and used for a long time, but I then disconnected it and plugged a different printer into that parallel port.
Since I only had one parallel port and wanted both printers attached, I bought the USB-Parallel Converter cable. It is an Inland brand. I got it at Micro Center on 11/20/2007, and paid $10.99 for it.
Both printers are still installed on an old desktop running on XP. I don't know if any of this helps you.
Good luck!I