Windows Server 2003 Extend Primary Partition

It is a common but terrible problem for almost every Windows Server 2003 user when free space on a disk partition especially a primary partition is insufficient. Usually, a primary partition is allocated with small size like 10GB or 20GB when it was created on computer. Thus, there is no doubt that the primary partition will run out of disk space along with more and more data stored on it. Do you need to repartition hard disk or reinstall system when primary partition is running out of disk space?