If you don't hear any sound when doing that, you probably have one of the flashcarts that needs to use the alternative moonshell2 loader which you can get from the moonshell2 download (although its recommended that you use the one from Xenon++'s mshl2tools...use whichever floats your boat).
I believe the flashcarts that need to use the alternative loader are Acekard, R4, DSTT, and maybe others.