Which has a HP proprietary 24-pin ATX connector that is basically a shrunk down version of a standard ATX connector with the pins in the same positions. According to HP documentation the board is a micro-ATX board.
My plan was for him to buy the following case and PSU...
And cut off the mini HP ATX connector from the old PSU, splice it to the 24 pin ATX extender using the butt crimps. Then use the new power supply to run everything, before finally adding in the 9800 GTX.
Seems to work as a plan in my head, anything I might have overlooked? PSU seems to be compatible with the motherboard, case supports micro ATX, No HP ATX to ATX adapters available that I can find.