So what do you do if you've taken all the previous courses but it has been so long that you don't remember anything?  It's starting to slow me down on assignments.

did you take notes? id look at those

redo homeworks you previously did for those classes.That's what I did

There's plenty of info online. For example, I'm in a java class right now and every time I have to refresh myself on how everything works. There's plenty of guides and tips to choose from. 

If you still have your old textbooks, look through them. Otherwise, Google is your best friend.

Well, I suggest that you review your old notebooks, considering you haven't thrown them away, look up for info on the web, and well, if that fails, hire a tutor so you can refresh your mind when it comes to this kind of stuff.  Do that, and your golden!

And if for some reason you have none of the above, you could always hunt down old classmates and see if they still do.

I do have notes, but I won't have them until Sunday when my parents drop them off and I am using the internet but it's so hard to find exactly what you need.  Thanks for the advice.