Here is a great post on how to resolve an error in Windows Live Messenger when it suddenly stops signing in. http://ee61re.wordpress.com/2010/12/14/unable-to-sign-in-to-windows-live-messengererror-81000490/ Delete the C:\users\<username>\AppData\Local\Microsoft\Windows Live\Contacts\<Windows Live ID> folder and then try signing in again.
When I attempt to install Windows 7 SP1 on multiple machines, I began the installation process as shown below. with the standalone and windows update version of the SP. It soon returns with this error: The troubleshooting page walks users through updating their anti-virus programs to update the mpfilter file. This wasn’t my issue….