In IE 11, try going to
Tools (Alt-X or the cogwheel in the r/h corner),
'Manage Addons'
Toolbars and Extensions should be selected by default on the left hand side.
Look for 'Shockwave Flash Object' in the right hand frame and verify that it is enabled.
Select the line and the botom frame will bring up the version number.
Check that this is the correct version number as the flash player you are installing. (e.g. make sure its not showing 11.x still)