Disable USB Drives

I am looking for an effective way to disable USB drives without disabling other USB devices. Therefore, disabling USB in the BIOS is out. The office I’m working for uses a CADD program which requires a USB device to work. However, we are worried about what might be copied to a USB drive. I found some advice on this site about going into the Windows 2000 registry to disable the usbstor driver from loading. Here’s the problem. It only disables it for 1 device. I inserted a Sandisk drive and then made the registry change. Then the Sandisk drive will not work. However, to test it, I then inserted a Lexar drive, and Windows went ahead and loaded the drivers and made it operational. I’m hoping someone has a better suggestion.