. . . . I need to transfer web designer premium 10 to a new computer . . . .
You don't - reinstall the software on your new computer and activate the product and check for updates.
If you find that the allowed number of activations has been exceeded then you need to contact Magix to have the activation counter reset - explain why you need it reset.
Copy website project(s) and any additional files used eg images from the old computer to the new.