Modern external USB optical drives never require a driver when used in any Windows os from WinME up. Windows ME, Windows XP, Windows Vista, & Windows 7 all provide native support that allows an optical drive to read a data or music disk and to burn a cd-r disk. No support for playing dvd disks, avi or mpeg video files, or for burning cd-rw or dvd disks. For those tasks, compatible 3rd. party recording & dvd decoding software is required.
When you plug a working USB optical drive into a working USB port, Windows will automatically install this drive, without user intervention, within 4-6 seconds and give you a notification that the drive is now ready to use. If it doesn't I'd first test the drive on a 2nd machine and then check the USB port(s) in Device Manager to insure all are working properly.
Some old early model USB drives did require a driver but not all. All usb drives built in the last 5-6 years should be 100% plug and play in Windows XP. What happens when you plug the drive into a usb port? Any errors, any notifications?