XP drivers are Windows device drivers written to enable hardware devices to
work in the XP environment.
Vista drivers are Windows device drivers written to enable hardware devices
to work in the Vista environment.
In some cases, there will be no difference at all other than the inclusion
of an operating system identifier which ensures that the device driver will
only work in the range of operating systems determined by the hardware
manufacturer. In this way, a hardware manufacture can ensure that older
products become obsolete..