Swerv,

For a quiet PSU, Fan then it will most likely have to be either a self build or buy an off the shelf PC and replace the PSU and CPU fans. I have a intel q6600 and std fan and its ok. Im sure you can get silent ones, but unless they are passive cooling(massive heatsinks) then they all make noise.

GTI-ITG or a guy similar in name posted a link to a sight that lets you customise a PC exactly how you want it. IF your PC is 4 years old then any off the shelf quad core will show it up especially in photoshop. I would sopec the system yourself and have somebody build it for you as you will get a far higher spec for your money. As an example Dell want £100 to add an extra 2GB of ram, this costs £30-£40 from most retailers!.