Why are viruses not considered living?

A living organism should be able to perform a number of processes in order to be classified as "living". These processes include such things as obtaining and processing food to release energy and reproducing. A virus is a strand of DNA or RNA, covered by a protein or lipoprotein coat, which can attack and insert its genetic content into a cell. This genetic content translates itself, and causes the formation of numerous copies of the virus by depleting cell resources, and in the end, as the virus replicas flourish, the cell explodes, spreading the virus replicas to attack other cells and so on. the virus does not obtain its own food, or do anything, really, without its host cell, unlike bacteria, for example. A virus also requires a host cell to reproduce. So, a virus cannot be really considered a real living organism,but then, it can't be called unliving either, so what is it really? Guess it's a virus!