On a Vista laptop with a on/off switch for Wifi, turning the switch on will trigger a lot of activity, killing performance and causing a lot of hard drive grinding.
The problem appears to be the auto-starting of mobsync.exe, which in turn starts up wmplayer.exe, which in turn does some kind of scan of its full database.
Where are the configuration settings to prevent this? For someone with a lot of music on their system this can result in a huge performance loss when flipping that wifi on (say, right after a flight or after coming out of power-saving mode). Is there a group policy setting I can set?
Try changing the settings on the "Library" tab in the Options dialog in Windows Media Player, specifically making sure "Share My Media" (under "Configure Sharing...") and "Retrieve additional information from the Internet" are unchecked.
You could try this to disable mobsync.exe