Weel, for this, We need to edit the registry..So First of all Backup Your registry.
Right After That, u need to do d following.
Open regedit ( Press WINDOW Key + R, Type regedit.exe ), and browse to H_KEY_LOCAL_MACHINE/Software/ Microsoft/Windows/Current Version/Polices/Ratings
Delete the entry named Key. restart Windows. open Internet Explorer, and goto tools-->Options then click the the content tab, and click disable, don't enter anything as the password and click ok, this will disable the password.