its downloaded and its tied to 1 computer.
Its not that big of a download either. If you don't have a fast connection you can download it at a friends place or whatever then install and active it from the computer you wish to you.
The requirements are pretty low. Its not that intensive of a program.
You just have to decide which one is least likely to fail before you take your test and which one would give you the closest experience to a real testing center.
So call up your testing center that you plan to take the test and ask them how big the monitors they have are. For me I went with my laptop. my desktop has a 24 inch widescreen. the center as 17 and 19 inch 4:3 monitors.
its a world of difference.
