When you use the Express Install option to install Microsoft Windows Server 2003 from the installation CD-ROM, only one-half of the drive space on the first logical drive is allocated to the operating system, leaving the remaining space unallocated.

NOTE: The Express Install option is only available if Emergency Management Services is enabled in the computer's BIOS.

This behavior is by design, because the Express Install option is designed to not use all the available driver space on the system partition.

To workaround this behavior, either use the Custom Install option when you install from the installation CD-ROM, or disable Emergency Management Services in the computer's BIOS prior to the install, and re-enable it after the install.