Just to update this little saga ... Managed to get to mate's house over weekend - 'pooter' not bootable in any mode, safe or otherwise.
Tried all sorts of dodges including HD reformat - no joy. Eventually brought said heap of rubbish home, to work on further. Wouldn't boot with another, already installed, HD. After a few more attempts, it now fails to even boot the Bios - nothing on screen at all
Have sent away for a boot post mortem card to see if that will provide a clue but this one has me even more baffled than usual. Duff display card, maybe?? Rage Pro 3 or similar. Otherwise, Mobo or processor?
Anyone any thoughts, please?
TIA