Hey Drummer!
Okay, go to your Manage my computer.
How you get there you say?
Right click on that little icon on your desktop (or start menu) which looks like a computer and has your computer name on it. Then select manage.
At the bottom on the left side of the window you will see an area that says Storage, click on the plus sign and it will open the tree revealing the removal storage (read tape drive), disk defragmenting, and disk management.
Click on the disk management. If you have the USB external HD plugged into your computer, and your computer recognizes the HD. It should be shown in this area.
In fact, you will see any zip drives you may have, tape drive, CD drives, and Hard Drives (USB included).
Each Hard drive will show you what if any partitions it has, and whether or not it is a format recognized by the server. if your computer tells you that it can see, it can see it. It may not be telling you size, due to a number of reasons, but it does not mean you have to re-format your HD.
If XP can see it, then 2003 should be able to see it (should being the operative word).
If you Disk Manager cannot see it, then leave the USB HD plugged in, and restart your computer, or right click on the device manager and select add new hardware. If you need help just further information just ask.
Below is an image of what mine looks like! Good luck!
