Windows Media Player Network Sharing Service/memory hog

As of recent my computer has been real sluggish, so I opened up task manager
and found that Windows Media Player network sharing was the source of my
problem. It is using over 50% of my 3 gigs of memory. I just recently
installed Windows 7 and don't recall this being a problem in the past. I have
media player setup to share all of my media over my network, but none of my
other devices are on. Is it unknowingly sharing media on a P2P basis? If so
how can I correct this feature? Media player is literally crippling my
computer with all of it's memory usage.