Third-party sites also are a gold mine of additional information not only for enabling or adding USB to Windows, but also for other operating systems. Just check the Web sites of any vendor who sells USB add-ons.
For example, RamElectronics has an excellent how-to on adding or enabling USB in Windows, Apple, Linux, Be, and Unix at http://www.ramelectronics.net/html/usb-howto.html.
But what about DOS? On its own, it knows nothing about USB devices. This can be a major hassle if, for example, you boot to DOS or start your PC from a DOS boot floppy, and then find that your USB keyboard and mouse no longer work--your PC may start, but you'll have no way of controlling it!
Or, even if the keyboard and mouse work fine in DOS, you still may lose access to USB peripherals such as an external drive or CD burner. Although there's no single, universal fix for this range of USB/DOS problems, there are solutions to each piece of the problem.
For example, you may be able to enable DOS support for a USB keyboard through a "USB/Legacy" option available in some PC BIOSes. You usually can access your PC's BIOS set-up program by pressing DEL or some other specified key during the first few seconds of system startup.
Once in the BIOS setup program, search the settings that relate to USB, and see if there's a "legacy" option available to you.
If so, simply toggling that one option may allow you to use a USB keyboard from DOS. If the option isn't offered or doesn't work, try visiting your keyboard manufacturer's home page to see if they offer a DOS driver for your specific brand and model of keyboard.
Alternatively, your PC's original manufacturer set-up CDs may also have DOS-level drivers, too; they're sometimes included with newer PCs to enable the use of a USB keyboard or mouse with the DOS-level "system restore" or "system recovery" software. You may find drivers in other odd places, too, once you start looking.
For example, reader Karl Tipple found a DOS driver for his USB mouse that way: Hi, Fred, I discovered that if you put the "hidusb.sys" file on your boot floppy and load it at the A: prompt in DOS, the USB mouse will then work in [DOS]. I figured this out when I tried to use a USB mouse in WIN98SE with [DOS-level] Drive Image and discovered that the PS2 mouse driver wouldn't work. Hidusb.sys is actually a Microsoft USB driver originally from Win98 but included in later Windows versions, too: Just search your system for the file, and it probably will be there.