When you boot the installation CD-ROM in order to install Windows Server 2003, the drive letter that is assigned to the System drive may not be what you expect.
If you wish the System drive to be C:, you can use the Setup process to delete all the drives except the installation drive. Alternately, install twice:
1. Install Windows Server 2003 to a partition other than the final partition.
2. Boot this initial install.
3. Right-click My Computer on the Start menu and press Manage.
4. Press Disk Management.
5. Right-click the drive that you wish to be drive C: and press Change Drive Letter and Paths.
6. Press Change and and select the C: drive from the list.
7. Press OK and OK.
8. Run Winnt32.exe to begin the final installation process. All existing drive letters will be preserved.