I listen to the teacher/professor in class, skim through the textbook, and almost always remember everything I need to remember for the test.
Believe it or not, this works. 1 hour of lectures is worth 3 hours of studying. But only if you're ahead of the class! As soon as the lecturer writes something you can't understand, it doesn't work. And that's why you have to study if you're lagging behind the classes.
This is why cramming is bad. Catching up to classes is an uphill effort.. you learn less and less per hour in class when you're lagging. If you want to have it easy, study up to the point that you have no trouble understanding everything from classes, then you can get by with minimal effort.
But since you're already behind, I think your problem is that you have no idea how to start. The best thing you can do is... just do it. It's like starting to exercise, the first few hours are the hardest, after that you get used to it. You no longer really care how hard it is once you start.
When you're studying and get stuck on a problem, you have the tendency to keep working at it or find info elsewhere. This makes your brain want to do nothing. Force yourself to just keep doing it. Some of the highest graded PhD graduates I know aren't very smart at all, they're just persistent. They have bad memory, have trouble with some basic stuff in life, but when they study, they put in full focus and only switch books to get references.
If your computer is really distracting you, unplug it, pull out the hard drive, and hide the Internetz (ethernet cable/wireless). If it's more effort for you to start up the computer than to study, you're going to end up studying. Just don't procrastinate by doing something else. It's going to be tempting to clean the bathroom, do laundry, anything to avoid studying.