Cannot detect USB Portable Hard Drive on Windows Server 2003.

I am trying to copy big files from a server using external hard disk. But I windows server 2003 unable to detect my External drive. Then I found out that my hard drive is detected by the system but I cannot see it because no drive letters  are assign to my drive, so we need to assign a drive letter to the portable drive so we can see it.

This is how I do it.
1. Click start and then Control Panel
2. Click on administrative tools and then computer management
3. On  computer Management click on Disk Management.
4. If you can see your external drive right click on it, then select change drive letters and paths
5. In the next window, click on "Add" then select the letter you desired.