This seems to be a problem related to WMP 11's ability (or inability) to
handle .avi files. More specifically, there is a problem to detect where
.avi files end, if they are corrupted or in the process of being downloaded.
When in Windows Media Player, right click on the top menu bar somewhere. Go
to file->Add to library. The list of folders you see are the folders that
WMP checks to find new media files. These "library folders" are the places
that you can browse when you are looking for media files through the media
tab on the Xbox 360. By default, media in My Music, My Pictures, and My
Videos are added to the library. Other folders can be added if specified.
If there are any .avi files that are incomplete (whether the file is being
downloaded, is corrupted, or whatever else) that are in your library folders,
wmpnetwk goes bananas. WMP 11 on your computer is trying to sync your files
with the 360, but flips out because it can't find the ending flags to .avi
files. WMP then starts consuming all of the resources it can find.
Solutions:
-Don't download files to your library folders while media sharing is enabled
(ex. downloading an avi from the web or any file sharing program to "My
Videos" will make your computer crazy until the file is done downloading.
Try downloading files to the Desktop then copying them over to whatever
folder when they are finished)
-Check your library folders for any corrupted avi files (worst case
scenario, copy all of your video files out of your library folders and add
them back one at a time, paying attention to which files cause the computer
to start using all the resources).
-Download the patch from Microsoft
...Just kidding there's no patch. Maybe someday though! We can only hope.