If you can't get her information the application will be considered rejected and you might not be able to receive any federal student aid. The most you would be able to get would be a loan called an unsubsidized loan.
I have another question for you based on Direct Subsidized Loans. Who pays the interest on this type of loan?
Actually the U.S Department of Education pays the interest on a Direct Subsidized Loan.
Ok and about applying for federal student aid, what can I do if I don't have any contact with my parents due to family problems?