” wmpnetwk.exe is a process of Windows Media Player Network Sharing Service.
The only reports I had seen of this using resources is with Win 7 RTM where Microsoft knew there was a bug, but said it would be fixed in the retail release of Win 7. However I do now see other reports about it.
If you don’t share or stream media files over a network, or you use a 3rd party media player like VLC or similar, then you likely don’t need this service running and you can Stop then Disable it in the Services Console. Just head over to Administrative Tools in the Control Panel, then Computer Management > Services and Applications > Services, scroll down until you see “Windows Media Player Network Sharing Service”, highlight, double click, then Stop, then Disable it. More about this here; http://www.addictivetips.com/windows-tips/fix-wmpnetwk-exe-in-windows-7/ “