Hi Max
Things don't seem so bad today.
Got my PC up and running using PS2 ports as you recommended. Good news is that processor, memory and hard disk appear to be OK. I have four USB out of the original nine working. I seem to have lost the sound output. When I run the audio trouble shooter it reports no audio device is plugged in. I have tried various devices but get the same report. When I click on the speaker icon (bottom right) audio output is indicated.
The worst scenario seems to be a new mother board. What do you think?