Open the Device Manager before you plug in the USB cable. After you plug it in, you'll see several device entries popping up, and their drivers will get installed automatically for most. 6\8 denotes that 6 out of 8 device entries have their correct drivers installed. So for the remaining 2, manually update the drivers and search for the drivers in the installation folder. Here's how to find the installation folder:
I'm pretty sure you're using the downloaded software to install it. So press the Win+R key to bring up the Run window and type %temp% and press OK. In the window that opens, look for a folder starting with 7zS or hp_web_release. If you open these folders, then you should find the setup.exe file, along with folders named Setup and Util. This is the HP install folder. Copy this folder to your desktop so that you can easily pass the address of this folder into the Driver update window. If you dont find the folder in the 'temp' folder, then go to C:\Temp and you should be able to find hp_web_release.