They're ALL used by the system. If you want to disable the windows update checking and get rid of one of processes within, go to Start > Control Panel > System And Security (If you use small/large icons, click windows update, then click change settings on the left) > Turn automatic updating on or off > Change the dropdown menu to "Never check for updates". This WILL leave your system's security at risk if you're not getting the patches and bugfixes, but will disable update checking.