If you mean you get a solid/flashing colour screen when you start up, it depends sometimes on how you put the cartridge in. If it works sometimes, just try taking it out and putting it back in and trying again a few times. I usually push in more on one side of the cartridge and alternate between sides until it works (usually only a few tries). I'd say that it's actually the taking out and putting back in of cartridges that makes the blowing in the game work, rather than the blowing itself.