I think Greg is correct in that you only need a license for each o.s. You don't have to have a separate XP license for each image you create if they are all for your use on one PC. I have a series of posts on my blog where I discussed the advantages of virtualization software with Rockwell products. You can find it here if you are interested: Windows 7 or XP or 98 or whatever with Automation Software Good Luck Doug