I encourage you to take some time by yourself and/or with your partner and answer these questions: Why do I want her to succeed so badly? Is it for her or for me? Ask yourself: How did I learn how to succeed? Did I have to do my own work?
Lastly, but most importantly, what is the worst thing that could happen if she fails seventh grade? What are the consequences? Summer school? Repeating seventh grade? By failing seventh grade - and either going to summer school or repeating -- your daughter can learn that she is responsible for the choices she makes about her studies.
Talk with the school counselor about parenting skills classes. There are also some excellent books at your local library that cover topics like study skills and helping children accept responsibilities.