Hi Scott, thanks for your response.
I had checked that but there was no floppy facility in the BIOS, however I've just been back in again and found that somehow the on board graphics and sound had become enabled... Go figure, I am sure I had turned them off when I updated the BIOS.
Anyhow, all is snappy again. maybe the occasional audio dropouts I've been experiencing will disappear also! :-).
I'll change the title to solved.