Basically, 있다 means "to have", while 없다 means the opposite, "to not have", but you have to insert the context you're asking really, for people to be able explain it better and clearer. As for "하고" it means "and", but as far as I know, it only can be used to join nouns in one sentence.

나는 숙제를 하다. "하다" means "do" 나는 숙제를 하고(and) 테니스를 쳤다. I do homework and play tennis. 나는 공부를 하고(and) 테니스를 쳤다. 나는 전화를 하고(and) 공부를 했다. 하고 is do plus and. "하"다 + 그리"고" -> 하고. "There is/are" is like 있다. "There is/are not" is like 없다. I hope that helps. Feel free to contact me. ^^