Booby
Whatever you do, (installing and updateting or unistalling) always as a
adinistratºr.
This is the key!
The installation as an admin is not enough.
You needed to login as an admin.
Can you gº to Windows Update, select Express (Get high-priority updates),
and apply all offered updªtes
http://update.microsoft.com
There are many pre-requisite files which are needed from windows update and
signature update with windows defender will fail until you hªve these files.
Install Windows Installer 3.1 v2 (3.1.4000.2435)
http://support.microsoft.com/kb/893803
Once that is finished, can you verify the update installs?
Can you please check the top version number, in Help, about? This should be
1.1.1347.0. If yours is a lower number, please do a new download and run
the downloaded file to update.
Otherwise, can you say more about your machine? Are you running full disk
encryption software? Have you run a scandisk recently?
Booby, with no information I'm guessing what it is what you need.
http://support.microsoft.com/kb/555375
Please supply more info.