Help with printing problem

I have installed my HP printer on my MBP and it works just fine when I need to print something. I've only printed some Pages documents, but I've had no problems. My problem is that every time I turn my MBP on and get the desktop, the HP Setup Assistant pops up (it happens when the printer is plugged in or not plugged in). I try to go through the setup, but where it shows to select a printer, it shows nothing so I cannot select anything. How can I fix this?