Updated Release - Where do we get them and how do we install them?

From the last webinar we watched, it was stated that updates are being released every week (or so) and we should keep an eye out for them as no notices are being sent out. My questions is…

Found where the update option is and downloaded release 4.0.178. While running the update, we received a “Files in Use” message regarding w3wp.exe. Selected the option to "Automatically close application and attempt to restart them after setup is complete. After clicking the OK button, we received another message "The setup was unable to automatically close all requested applications. Please ensure that the applications holding files in use are closed before continuing with the installation. Since we did not have Boss open, clicked the Ok button.

What is the w3wp.exe application and how to we close it when running updates?