Here's what it means technically: When Internet Explorer closes, it
relinquishes the blocks of memory it was using so that they can be made
available to other programs. There is a block of memory that Internet
Explorer is unable to relinquish because it cannot get access to that
memory. As a result, Internet Explorer is stuck in a kind of computer
purgatory, partly closed and partly open.
Here's what it means practically: An add-on that opens with Internet
Explorer doesn't want to close when Internet Explorer says "time for us
to close." Your mission is to discover what add-on is causing the
problem. You can view the add-ons at Tools > Manage Add-Ons.
Disable the add-ons one at a time until you find the troublemaker, then
contact troublemaker's technical support. In my case, it was my beloved
ad blocker, and the only way out was to uninstall the program.
The other possibility is that one of your RAM chips is going bad. That's
easy enough to check with the Windows Memory Diagnostic at
http://oca.microsoft.com/en/windiag.asp
