wmpnscfg.exe is a process associated with Windows Media Player Network Sharing Service Configuration Application from Microsoft Corp.. It is used to share Windows Media Player libraries.
Windows Media Player 11 can share media between different computers on the same network, and can even share media with the XBox 360 as well. For this to work, there’s a network sharing service that shares the library even if Media Player isn’t open.
Both of these processes are part of the Windows Media Player Sharing system, so if you use those features you should not disable it.
Non-system processes like wmpnscfg.exe originate from software you installed on your system. Since most applications store data on your hard disk and in your system's registry, it is likely that your computer has suffered fragmentation and accumulated invalid entries which can affect your PC's performance.

In Windows Task Manager, you can see what CPU, memory, disk and network utilization is causing the Windows Media Player Network Sharing Service Configuration Application process. To access the Task Manager, hold down the Ctrl + Shift + Esc keys at the same time. These three buttons are located on the far left of your keyboard.

This process is considered safe. It is unlikely to pose any harm to your system. The wmpnscfg.exe file should be located in the folder C:\Program Files\Windows Media Player. Otherwise it could be a Trojan.

This process is not considered CPU intensive. However, running too many processes on your system may affect your PC’s performance. To reduce system overload, you can use the Microsoft System Configuration Utility (MSConfig) or the Windows Task Manager to manually find and disable processes that launch upon start-up.

Use the Windows Resource Monitor to find out which processes and applications write/read the most on the hard drive, send the most data to the Internet, or use the most memory. To access the Resource Monitor, press the key combination Windows key + R and then enter 'resmon'.