What job can I get at 14 years old, using the computer only?
Depending what your skills are, there is so much anyone can do online! Check out Fiverr.com for some ideas.
What skills and qualification do you have to offer using the computer only? For example are you fluent in some programming language, are you good with designing things (web sites, digital art, banners), are you a good writer, etc. ?
When you are looking for a job on the internet you have to have some direction as you will hardly find a 'traditional' internship where you can start out without any prior knowledge and are being explained step 1,2,3 …