Re: loud fan sound
The paperclip thing is safe. I use my old 200W PSU that I pulled from my HP system when I swapped for 500W to test components outside of PCs. You can use anything (wire, paperclip, or other metal object) to short the green wire to any black wire (the green wire turns the PSU on). That way you can test the fans.
You can do the paperclip trick without anything connected to turn on the PSU fans. That way you can see if the PSU fans are making the noise.
If none of the fans make any noise when they're out of the case, it could be that a fan is hitting part of the case. My HP has this problem, where the back fan will hit into the plastic thing holding it or the fan grill on the back. I haven't found a fix for it, but it's a minor annoyance at most.