OK, really dumb question, but my computer shut off the other night and I discovered my CPU fan wasn't running. Was badly dirty with dust, etc so I took everything apart and dusted, vacuumed, blew out with air to clean the tower out. My question is when putting everything back together I forgot which way to install the Northbridge and CPU fans!! Yep I'm dumb!! Do I install so they blow ONTO the Northbridge and CPU, or do they suck air AWAY from both of them??? I feel SO stupid!! 