How to view the Update log in Windows:-
Click Start, and then click Run.
In the Open box, type: %windir%\windowsupdate.log
and then click OK.
Scroll down towards the bottom for the latest entries to locate the
error code(s) associated with the latest failed attempt to
download/install. If appropriate copy and paste the error codes
into this thread so someone may be able to assist you. On the other
hand, you may be able to find the error code and other suggestions
by searching the Newsgroup.
Also check Windows folder for file called KB******.log (****** =
number of update ie KB896688) and post the contents of the failed
update.
This may provide further clues as to why the update failed.
How to read the Windowsupdate.log file:
http://support.microsoft.com/?kbid=902093