Steinberg site Downloads

I want to know more about downloads in Steinberg site.
if I download for example Cubase 7 does it work in my pc?
do I need to purchase something?

How would anyone know if it will work, when you are not giving the least bit of information…
Obviously apart from a computer that has the requirements necessary for Cubase 7, you need a Cubase 7 License to run it.