Internet Explorer window automatically closes when I open a new wi

This just recently started happening .... when I open up a new internet
explorer site, any othr one that is open, is automatically closed ... a bit
frustrating. Not sure what happened and why it is happening. This following
sequence.....Internet Explorer > Tools > Internet Options > Advanced tab In
the Browsing section, uncheck "Reuse windows for launching shortcuts".
This box was already unchecked ... problem still exists. Thanks, Brian