Windows Update Agent, download new Windows Update files.
Syntax wuauclt Options Options: /a or /ResetAuthorization Initiate an asynchronous background search for applicable updates. If Automatic Updates are disabled, this has no effect. /r or /ReportNow Send all queued reporting events to the server asynchronously. /DetectNow Initiate detection right away, Query the WSUS server immediately to see if any new updates are needed.
WSUS uses a cookie on client computers to store computer group membership when client-side targeting is used. By default this cookie expires an hour after WSUS creates it. If you are using client-side targeting and change group membership, use /ResetAuthorization /detectnow to expire the cookie, initiate detection, and have WSUS update computer group membership.
If Windows Update has been blocked, disabled or failing for a long period of time a long history of updates will build up in the archive, this can cause high CPU use. Resetting the client can help with this, but it will take a long time to run Windows Update afterwards.
Navigate to: Computer Configuration > Administrative Templates > Windows Components > Windows Update
Open this and change the "No auto-restart with logged on users for scheduled automatic updates installations" to ENABLED
In the control panel choose Update and Security > Windows Update.
Click "Check for updates"
Alternatively set this in the registry:
NoAutoRebootWithLoggedOnUsers (DWORD=1 to disable automatic reboots)
C:\> wuauclt /a /DetectNow
C:\> wuauclt /r /DetectNow
“We must always change, renew, rejuvenate ourselves; otherwise we harden” ~ Johann Wolfgang von Goethe
WUSA - Windows Update Standalone Installer.
wuauserv - The Windows Update Service
Windows Update Troubleshooting - completely reset the Windows Update client settings.
AskWoody.com - Advice on Windows Update conflicts.