I need to reset my master key password for my dsi

The best way out of this is to go to parental conrols in system settings and when it asks "change system settings?" click yes. when it brings up the numeric keypad select i forgot, and tap i forgot again. Now you should be shown a screen with a number at the bottom, this is known as "the inquiry number", next you need to log onto this web page http://wii.marcansoft.com/parental.psp and enter the inquiry number you just got. next set the current date in your timzone and click reset code. And now you should be good to go with your dsi parental control free! :) Hope this helps