var s:string;
begin
s:=hotkey1.Hint+#0; // Alt+A
RegisterHotKey(form1.Handle,GlobalAddAtom(@s[1]),MOD_ALT,byte('A'));
end;

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;  var Handled: Boolean);
begin
if msg.message=WM_HOTKEY 
then begin
ShellExecute(………
     end;
end;