Sorry to get back so late.
My system was working perfectly until a week or so ago - no power supply failures that I know of.
I have not replaced power supply yet but did find specs (below).
After way too many attempts the system booted up this morning and is running perfectly (I'm afraid to turn it off!)
In the meantime I connected the system fan directly into the PSU, (which previously was added onto the HD molex connector cable.)
the power supply came with a ATX Mid-Tower Case - ULTRA "ULT33071", which Tiger Direct highly recommended.
These are the specs of the PSU:
Connections:1 - 20/24 Pin Motherboard Connector1
4 Pin +12V Motherboard Connectors
8 - 4 Pin Molex Connectors
2 - 4 Pin Floppy Power Connectors
1 - PCI Express Connector
2 - SATA ConnectorsOutput
AC INPUT 115V/230V 10A/6A 60/50Hz
MAX OUTPUTCURRENT +5V +3.3V +12V -5V -12V +5VSB
(30A 18A 20A 0.6A 0.6A 2A)
Total Output Power:400W (Full Load, Nominal Input Voltage)Efficiency:70% Typical at Full Load and Nominal Input Voltage
Don't know if this helps but I am researching new power supplies at this point...