For registration, updates, or upgrades, see the information in the Customer Service section linked below and in Support. You can contact CS and change your registration from Mac to Windows, or register or do a transfer of ownership if you purchased a previously registered system used. Depending on your situation, you can get the Windows PT LE 5.0.1 software, or you can upgrade to version 5.1.1 for $50. The 5.1.1 upgrade (not update) is a full installer and does require previous installation of Pro Tools on your computer, if you need to get going right away. See the
PT LE 5.1.1 Upgrade information in particular.