Partition resizing software for Windows Server 2003 is required while disk management in this system has no extend volume function in Server 2008 and 2012. Users of Server 2003 often resize partition by reinstall system or repartitioning with acceptable amount to boot partition when first installed.
Step 1: Run Partition Expert, Click on one Drive with enough free space in it, and Click on Resize/Move Volume from left function guide column.
Step 2: Drag the handle on the left to shrink this partition and make free space from it. You can see the direct effect shows below, how much free space have made, how much space left, then click OK.
Step 3: Now we can use this unallocated space to extend C Drive on Server 2003, still, we click on C Drive and Resize/Move Volume, this time, We drag the handle rightwards to the end of system partition, Then OK, following disk map shows the result in real time, but not take effect now, We click Commit to confirm all the operations.
That's how Partition Expert works to extend partition on Server 2003, within 3 steps, You can also extend C Drive with Partition Extender, another Macrorit Partition tool, within one step, here is the guide on how to extend Server 2003 C Drive in Partition Extender.