To transfer or re-activate license you need to deactivate current “Hardware id” at personal area www.paintstormstudio.com/login.php After that, you can register Paintstorm from any MAC or Windows PC again.
If you don’t have password You can get it at the bottom of LOGIN page by “Forgot your password/First time login” link
If you have several licenses and can’t understand wich of Hardware id you need to deactivate, you can write to info@paintstormstudio.com and ask to reset your account.
You can deactivate license only once in a week. If you want to paint at several PC every day, you should buy several licenses.