After you log in at mpconline.mpc.edu, your MPC Online courses will be listed in the My Courses block. You can limit the list to just those in a particular semester by click All, then picking the semester.
You can hide courses from your list by clicking the eyeball symbol to the right of the course name. When you have a hidden course, you'll see an option to Manage hidden courses. To un-hide a course, click Manage hidden courses, and click the closed eyeball to open it.
From within any course you can return to the home page by clicking the "My Home" link in the red bar in the upper left corner.
Related topic: What if I don't see my course listed in MPC Online?
Contact the MPC Online Help Desk if the above suggestions don't solve the problem.