The tag below your question says that you are using TurboTax Online. If that is true, you don't install anything. You can access your TurboTax Online account from any computer, and from different computers at different times.
If you are actually using the CD/download TurboTax software, and you install it on more than one computer that you own, you have to use the same TurboTax account when you activate each installation.
