i thought that too, oldexpact and sqad, but i just read an authentic definition that says 'most living things are made of cells,,,' and that got me all confused..
Hmm that rather depends on your definition of living.
A virus when outside a host is simply a set of (rather complex) chemicals. It invades a host cell and hijacks the cells functions to reproduce.
You could argue that a virus is a life form that is not made up of cells.
However a virus uses cells (albeit not it's own) in order to perform the functions most commonly used to define life. Therefore a lot of people (me included) would say that a virus is only really alive when inside a cell and outside of a cell it's more like a seed with only the potential for life