NOMDM425.SYS NOMDM425.SYS is a device driver that allows international Presario 425 models to free up DMA and IRQ channels for use by other peripherals like Soundblaster. WHO SHOULD USE: International models of the Presario 425 with ROMS dated before 10/26/93 will allocate DMA and IRQ channels to the system board option slot and thus will conflict with other peripherals like the Soundblaster. NOMDM425.SYS de-allocates these DMA and IRQ channels from the system board option slot and allows them to be used by boards plugged into the two internal ISA slots.