A:  Below is some code that will help if you want to terminate ALL tasks, no questions asked.

Note:  To terminate ONE app, see FindWindow.

A word of caution, before you run this for the first time, make sure that you save it and anything else that may have some pending data.
 

procedure TForm1.ButtonKillAllClick(Sender: TObject);
var
  pTask   : PTASKENTRY;
  Task    : Bool;
  ThisTask: THANDLE;
begin
  GetMem (pTask, SizeOf (TTASKENTRY));
  pTask^.dwSize := SizeOf (TTASKENTRY);
  Task := TaskFirst (pTask);
  while Task do
  begin
    if pTask^.hInst = hInstance then
      ThisTask := pTask^.hTask
    else
      TerminateApp (pTask^.hTask, NO_UAE_BOX);
    Task := TaskNext (pTask);
  end;
  TerminateApp (ThisTask, NO_UAE_BOX);
end;