With so many people now using the weak NT opening bid, you need a convention over the weak NT bid. DONT is not good over the weak NT bid because you cannot double showing a balanced hand with equal values. The convention I like to use is Modified Cappelletti. 2C is a hand with 6D or a major and a minor. Partner bids 2D. Partner may bid 2NT asking for the minor, if he cannot support the major. 2D is a hand with H & S. A 2H or 2S is a hand with 6 cards in the suit bid. 2NT is for the minors. Double can now be used for a hand that is balanced with equal or better values. Partner can now use stayman & jacoby transfers. Go to the internet or e-mail me for more info on Modified Cappelletti.