How to trap the system error when a user tries to access a floppy drive with no disk in it

Problem/Question/Abstract:

How can I trap the system error that results from a user trying to access a floppy drive that has no disk in it. I want to show my own error message etc., rather than the system one.

Answer:

procedure TForm1.Button1Click(Sender: TObject);
var
  ErrorMode: word;
begin
  ErrorMode := SetErrorMode(SEM_FAILCRITICALERRORS);
  try
    if DiskSize(1) = -1 then
      ShowMessage('No disk in drive A')
    else
    begin
      { Your code }
    end;
  finally
    SetErrorMode(ErrorMode);
  end;
end;