OK I am shooting from the hip here, but there are 2 thing that might be happening here.

  1. ) Even if the printer is working fine and the program opens and all that, a driver was not totally installed.
  2. ) There are remnants of an old printer program

What you can do is to uninstall your current printer program and drivers and see if the “New hardware found” window shows up again. If it does, go to My PC > properties > Hardware > Device manager > View > Show hidden devices and look for the guilty device that is given the error and remove it.

Otherwise reinstalling the printer program and drivers should remove the popup.