The RAM culprit here is Windows Media Player(WMP); it's eating up 2.41GB of RAM in your log in the form of wmpnetwk.exe.
In Windows 7 by default, WMP runs several background services which are used in sharing media across a local network (e.g. to a network-connected TV.) If you're not using WMP for this kind of sharing, then you can turn the services off. Your SONOS system may or may not be using WMP's network capabilities.
To do so, type services.msc
into the Start menu search box and press enter. In the Services control panel that opens up, change the Startup Type of the "Windows Media Player Network Sharing Service" to Manual
Reboot, and the RAM problem should be gone.
If you later find that your SONOS doesn't work, you can start and stop the necessary services manually from the Services control panel.
Edited by Andrew, 26 October 2012 - 08:22 PM.