Although Windows Server released many editions, like Server 2012, Server 2008, and Server 2003, the older one, Server 2003 still have a large group of fans around the world (Microsoft Windows Server 2008 R2 Standard SP1 OEM $549.99, while Microsoft Windows Server 2012 R2 Standard OEM $659.76 in amzon); price is not the reason people kept Server 2003;
Many are used to provide service like download center, or blog sites service. Along with the frequently internet using, there are more requires on Server 2003
Run Disk Partition Extender Server Edition, it will quickly load the disk map. C partition with a flag is located at the first section. Chick on it, then Next bottom become clickable, ok, Next, the windows shows a ball that can be drag to distribute space or the column below are available to type specific size. OK to continue.
After the operation is committed, the software will reload disk map to display new partition size you extended. Besides, you can run Disk Management or WIN+R to run diskmgmt.msc to see the disk map synchronously. I think after the extension, you'll see the result intuitively; the performance of running Server 2003 will improve accordingly.