My new PC is pretty loud. How do I tell exactly what is making all the noise? I think a lot of it may be the processor fan, so I've been looking to replace that. My temps seem to hang around 45 degrees for the CPU. Is that good? That's with a heatsink/fan combo that came with the unit.

If I were to get a better unit that would be quieter and cool better, what would you suggest for an AMD 2100+?