Many people have replaced their original Shuttle PSU when it failed with other PSU's due to the massively over-expensive replacement Shuttle PSU's.
Please tell us the model of Shuttle, and the CPU that you have so that someone here can gauge the real power requirements of your PC and suggest a replacement.
Also for the sake of it cropping up later, can you tell us the nature of your fault. Some PSU faults look identical to Motherboard faults.
If your PSU has not failed, have you identified it as the main source of noise in your PC.? And also what is the second source of noise, if you are looking for a serious noise reduction you might end up with a whole new PC rather than just a PSU swap, there have only been a handful of truly quiet Shuttle PC's out of the dozens of models made.
Main PC, P180, CM Silent Pro 500M, Phenom 840 @ 3.6GHz, 8-GB @ 1,866MHz, 256 GB Samsung 830, 500-GB 7K500, MSI 660Ti Twin Frozr, PC is quieter than my monitor :o
Server, 6-TB RAID-5 array, + 2 x 2-TB backup drives, 380W Enermax Pro82+, 4x very quiet fans, positive pressure only, no exhaust fans
Living Room PC, 3500+, 2-GB RAM, HD501LJ