the count down ca be adjust in control panel, system, advance setting, startup and recovery (parameter), Or by the boot.ini. Maybe the computer reboot before the update are fully installed?
check this log file : c:\windows\SCTWindowsUpdates.log to see if everything finish fine.
run a scandisk to check for bad sector.
Login as admin and go to the windowsupdate web site
AutomaticUpdateTime is by default set to 16 minutes. Maybe your update take more than that, computer reboot during the installation... HKLM\System\CurrentControlSet\Services\Windows SteadyState\Parameters