I have checked what it seems to be the official website, but the game doesn't appear to be available anymore. The SpinTop developer doesn't have the game available for purchasing or buying.
In this case, the only way to move the game is by network transfer or using a USB flash drive. For network, connect the two computers, to a network, then share the folder where the game is installed and copy it on the new PC. For a USB drive, transfer the installation folder to the portable unit and then plug the device to the new computer.