What model scanner do you have?

Built-in where? How? A driver is a piece of software that runs in the
operating system. It can *not* be built into a hardware device.

That's *highly* unlikely. I think Brother just gave you bad info.

Almost certainly, the only possible solution is to get the needed
driver from Brother. Check their web site--you need the appropriate
driver for the combination of Vista and your model scanner.

But be aware that such a driver may not exist. One of the potential
problems with going to a new operating system is that the
manufacturers of all your devices may not provide drivers for them,
particularly if they are older models.

Also note that sometimes drivers don't exist when the operating system
first comes out, but they are developed and released later. However in
this situation, enough time has gone by since the release of Vista
that if they were going to provide the driver, they probably would
have already.