Select object, then Delete Key or Move Command

I have a machine, whem a drawing is open in model space, the user selects the object, then can manipulate the selection. I.E. delete, move, copy, etc.

Recently, when the object is selected, then either the delete key, or c toolbar command like move, cancels the seletion set and evokes the command. At times, the object can't be selected after the ciommand.

This happens on only one machine. A new drawing from a templete, or opening an existing drawing.

Has anybody seen this before? Any suggestions?

Thanks.