The MP-840 Windows driver likely refers to a device driver for a specific product, potentially a mouse, keyboard, or gaming peripheral with the model number MP-840. However, based on the model number alone, it is not immediately clear what exact device this refers to, as the MP-840 could be a model from various manufacturers. MP-840 could refer to a specific model of gaming mice, keyboards, or other peripheral hardware.

The process for installing a driver for the MP-840 would depend on the exact device it corresponds to, but I can provide general instructions on how to install drivers for peripherals (such as mice or keyboards) on a Windows computer.