While I was recently rebooting a SBS 2008 server, the system had some pending Microsoft updates that needed to be installed. The server hung on “Installing and Configuring” 1 of 3 updates with 0%. I left it at this state for about 20 minutes and ended up forcing a hard shut down. This is commonly due to an XML file that is used for the installation process is corrupt.
My fix was to boot into safe mode with DOS prompt, browse to C:windowswinsxs and rename pending.xml to pending.old, reboot machine as normal.