What are the rights of a widow?

This is an extremely broad question, too broad for an answer that will help you. The question has to specify the type of legal right involved, such as inheritance where a spouse has died with a will or without a will; whether there are children of the marriage or children of the marriage and of a previous marriage or if the legal area involves rights as to joint property as opposed to rights in the estate itself. In adition, since this question was initially placed in "Debt Responsibility" it is possible that the thrust of the question is as to liability for a spouse's debts, rather than rights to inheritance. Another must is identification of the state in which the decedent died. Different states have different laws regarding such rights. Some states may have minor variances from one another, whereas some may have very significant differences. Unless the state involved is known, no one can give a helpful answer. In fact, some generalized answers may do more harm than good if such answers overlook some variation.