Fact: KB2670838 is a Prerequisite Update for IE10 <edit> and/or IE11. </edit>
Fact: If KB2670838 isn't already installed, it will be installed for you when you choose to install IE10
<edit>
...and/or IE11 - along with all other prerequisite updates.
- IE10 Prerequisites include KB2729094, KB2731771, KB2533623, KB2670838 & KB2786081.
- IE11 Prerequisites include KB2729094, KB2731771, KB2533623, KB2670838, KB2786081 & KB2834140.
Fun Fact: As of 12 January 2016, IE11 will be the only version supported in Win7. See http://blogs.msdn.com/b/ie/archive/2014/08/07/stay-up-to-date-with-internet-explorer.aspx
</edit>
Fact: IE10-for-Win7 is not ready for "prime time" - which is why it's not being pushed via Automatic Updates yet.
Fact: When Microsoft decides to push IE10 via Automatic Updates, free support will begin - but for now, you're on your own.
Tip: Stick with IE9 for the time being & save yourself a lot of grief.
PS: No one from Microsoft Support monitors this peer-to-peer support forum.
[Last Revised (as marked) - 15 November 2014]