Сan you install on several PCs or do you need to purchase a license for each PC installed on?
The program is not available anymore, which means it's impossible to buy it. As far as I know, the developers offered multi-license packages that allowed you to install the program on multiple PCs, but since it has been discontinued, this is not available anymore. You will have to use another application. Browse the database of Software Informer to look for something else.
The product is no longer updated: http://www.arcsoft.com/totalmedia-extreme/?siteID=de_Jpa6m7uY-Dcw3VcPDYiMlH0LkYXoJpA