With the game loaded, right click on your No$Zoomer, go to OTHER or press R button on your keyboard,
and you should see an EXTRA option in there.
If you enabled the Menu on No$Zoomer, it is also located on OTHER, with H button as a shortcut.
To OP, just enable the EX0 on the No$Zoomer EXTRA option.
But don't disable it after that, it will only cause your game to freeze.
Slow game speed on DeSmuMe is normal, turning the Sound off may increase the speed(a bit).