[dec]

Hola,

Algo así podría hacerse, más o menos, tratándose de Delphi:

Código Delphi [-]
unit UfrmPrincipal;

interface

uses
  Forms, Windows, Messages, Dialogs;

type
  TfrmPrincipal = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    procedure AppMessage(var Msg: tagMSG; var Handled: Boolean);
  end;

var
  frmPrincipal: TfrmPrincipal;

implementation

{$R *.dfm}

procedure TfrmPrincipal.AppMessage(var Msg: tagMSG; var Handled: Boolean);
begin
  if (Msg.message = WM_HOTKEY) then
  begin
    if (LOWORD(Msg.lParam) = MOD_CONTROL)
      and (HIWORD(Msg.lParam) = Ord('O')) then
        ShowMessage('Pulsaste las teclas "CTRL + O"');
  end;
end;

procedure TfrmPrincipal.FormCreate(Sender: TObject);
begin
  Application.OnMessage := AppMessage;
end;

initialization
  RegisterHotKey(Application.Handle, GlobalAddAtom('MiHotKey'), MOD_CONTROL, Ord('O'));

finalization
  UnregisterHotKey(Application.Handle, GlobalAddAtom('MiHotKey'));

end.