|You may have given permission for it to be downloaded and installed, or just installed , but that doesn't necessarily result in it was installed successfully.|
Go to the Microsoft website, then to the Windows Updates page, and look at your Updates History - look for KB2572073 - it should be near the top of the list - it will say whether it was installed successfully or not - if it wasn't there's probably an error code for it you can look up.
If that doesn't help, KB2572073 is an update for .Net Framework 2.0. If your Net Framework 2.0 installation is corrupted, the update may not "stick". Go to Control Panel - classic view - Add or Remove Programs, find the listing for Microsoft .Net Framework 2.0, and un-install it. Then install it again - either by searching for the download for it on the Microsoft web site, or by using the Windows Update web page to do an Express search (if it's not listed try doing a Custom search and look in the non selected entries), or Automatic Update may list it sooner or later.
If .Net Framework 2.0 won't un-install, there are ways of removing it in any case, e.g. with a cleanup program available from the Microsoft web site.
Note that if you have Catalyst installed along with ATI video drivers, Catalyst requires that .Net Framework 2.0 is installed. You may get error messages from Catalyst after it has been un-installed.