Yup. In the general sense of the term "virus" (any malware that can be installed on a computer), there are some kinds of malware, usually called downloaders, which can actually download more malware...
yes but no because they are competing againt whatever they are trying to get and not only that they need to stick together to help each other get rid of whatever...almost like a stomach virus or a...
If you have these viruses i suggest you get rid of them A Trojan is a virus that tries to install itself on your computer and take up space A script virus can be located in the hardest to find spots...