Well for a start, what is the voltage into and out of the big power inductor? One side should be fed from the PCIe plug through MOSFETS and will be a chopped 12v, the output side needs to 10v or more depending what the PIC is setup for. (Sidehack confirm?) Somewhere in this thread the output is mentioned.

Anyhow, if the low side of the inductor is less than that, probably dead PIC and the regulator/dpot is working off of preset defaults. If the voltage is zero the I'd guess the FET's failed open but typically they fail as a short.

I suppose if you have a PICkit programmer you can follow the heart of this thread and try to readout what the PIC has stored in it. After saving that (possibly corrupt) file might as well see if the PIC can accept a reprogram for lower voltage better eff...