|Gently stop the fan in question with your finger or start up the pc with the fan blade blocked. If the noise stops then you have the right fan.|
For the PSU fan that you can't reach, with the PC off put a screwdriver just far enough in to keep the fan blades from spinning but not so far that it touches any of the internal PSU circuitry. Then start up the PC and check for the noise. (You don't want to put the screwdriver in when the fan is spinning else you're likely gonna break a fan blade)
Obama's a 2012'er. That explains EVERYTHING..