Hello!
Our license states that you can only have Band-in-a-Box installed on one computer at a time. However, we understand that customers often have multiple computers, get new machines, or need to travel, so your activation code is good for installation on three personal computers. If you want to free up an activation, we recommend releasing it from the old machine if you won't own it or use it anymore.
As a general rule of thumb, I don't typically recommend copying any program directory to a new location. For a lot of programs, that won't work, as there's usually files stored elsewhere on your computer that tell the program its a legitimate install, but also files or aspects of a program may get installed to different paths or locations that you may not always know where to look for. Some programs even have protection against copying things to prevent sharing it with friends who haven't paid.
In our case, files get installed into different locations, so to ensure that you have a complete and proper install, it's best to install from your original media, be it downloads or a physical copy like a harddrive or flash USB stick. That way you know everything is where it should be.