what is an (active x control) on a dell m.e, computer

ActiveX controls are kind of like blocks of programming code, except
they are organized and packaged into tidy objects.  For example, a
programmer can have an activex control for Excel.  If they include
such a control in their program, they can easily have their program
do/get things with an excel spreadsheet.

You missing an activex control?  sometimes they go missing from your
PC, and you need to get them back.