Perhaps the biggest part of lowering a problematic computer usage habit is to find something else to do with your time. If unhealthy levels of computer/internet usage have become a part of your lifestyle, there will be a void, by definition as you reduce the amount of time you spend glued to your laptop. Here's a list of other things that can fill up that time.
This reminds me of a cute point I dreamed up one day. At the end of living a good life, we'll all get to see the score we got. You get big points for helping other people, and big points for going on adventures, but even for little, common activities, you get points. Things done outside count for more than things done inside. You get double points whenever you do the activity with anyone else (but you still get points for doing something, even if you can't find someone to do it with). You don't get points for randomly watching T.V., or randomly surfing the internet, and the points you get for doing so in a non-random way don't count much at all. Learning and personal development add significantly to the points of any activity. Variety also figures strongly in the score card; doing something (safe and valuable) for the first time gives you lots of bonus points. Variety of locations (even countries) also factors in.
Silly perhaps, but you could have fun coming up with your own way of scoring "Life". And the point is that wasting your time, such as what happens when you are crouched in front of the computer for hours on end, is not worth very much, besides the relaxation it provides to a point. What else can you do to score high in Life: take a look at the list above.