Have you looked into Junior Achievement? It has a lot of great resources to help you figure out what kind of business you are interested in starting. Here is the link: http://studentcenter.ja.org/Business/Pages/default.aspx Good luck!!
Hello! I like to think of it this way- I've heard a saying that the amount of money in your bank account is directly proportional to the amount of value you can add to other peoples' lives. There are exceptions to that, but using that as a rule, with your unique skill set (everyone has one, and it's constantly developing) and history so far in your life, where can you add the most value to other peoples' lives? It may not come to you right away, but continue to ask yourself that, as well as the great suggestion in the previous answer "how can I sell this/make money off this" and eventually you'll be onto something. And if that first something doesn't work, it will lead to the next something. If you remain persistent and use all your experiences, you'll end up in a good place!
You may want to consider exploring functions such as Sales, Marketing, Public Relations, HR, Finance.
You can start by assessing your strengths (i.e. what subjects do you enjoy or are good at)? Also, try to get internship or work experience opportunities within each area to gain an understanding of what it would entail.
I'm not sure we can give advice about that. You haven't specified what you like to do with computers, nor have you specified what kind of business you had in mind. You should probably figure out what your passions are (making movies, programming games, fixing computers), and then ask yourself, "How can I sell this? How can I make money off this?" Then you're on your path to figuring out how to make a business.
While you can do different businesses or related activities, as others mentioned, the best approach would be to get started with something which excites you, something that you’re passionate about. In the long run, things do get mundane(and that’s true of everything) and your passion is what keeps you driving and achieve great heights.
But, if you’ve not figured that stuff out yet but want to still get started. You can start with anything small that you’ve probably some knowledge about, your friend/family are part of (any business that you have an opportunity to easily get involved with) where you’d start learning the tricks of the trade and different aspects of it and maybe, you’ll find your passion along the way. Additionally, you can opt to study entrepreneurship and similar courses if you plan to take it formally in the long run.