Attach a correct transcript to your application, as stipulated in the application packet. Do not lie about your transcript, and do not avoid sending it when required.
Fill out the "additional information" section of your application. This may also be called "clarifications" or " special circumstances." In this section, state that you have received bad grades in the past. Give a reason for those grades, and discuss what has changed in your life so that you will be able to earn good grades in the future.
Find the email address for the dean of the department to which you are applying. Write and request an audience to talk about the bad grades you have received in the past. If the dean can't meet with you in person, send an email in which you explain why you received bad grades and what you plan to do to ensure that this does not happen again.
Email the dean of students at the college or university to which you are applying. Explain the situation and explain how important it is to you to be accepted by this school.
Go along with any probation period that the school may require.
Keep trying. If you do not get in the first time you apply, continue the process and repeat the steps, to show that you are determined to be a good student who is capable of doing good work.
Between applications, take classes at a community college near you. Make sure you pass those classes with excellent marks. Each time you apply, you should have better grades to show on your transcript, and you'll be able to talk about your improvement when you speak to the deans again.