Almost NO drivers are around for Advent Computers. I found this BIOS update after phoneing PC World who said the motherboard manufacturer was Uniwill. I eventiually found the driver by searching google for the chasis number (340S2) on the back. The drivers are out there but you have to search.
To use the BIOS update, copy the files to a floppy, then start the computer to a command promt (not from Windows) then type "A \Flash828.exe 340s108.rom" - ie the flash utility followed by the BIOS update