I've just installed a new twin fan Power supply, so I now have 2 fans in my pc, instead of the single outlet fan I used to have. I have one directly over the CPU (PIII 500 ~47 deg C) and one as an intake at the back of the PSU. I've noticed that the side of my case is getting warm (not hot) around the area my hard disks are located, but the hard disks themselves are getting quite hot.
My case is quite enclosed at the front with only a few slots for air to get in down each side, but I have another space for a fan at the back. Would putting another fan in be advised/help or would it reduce the airflow (it would be directly underneath the intake fan)?