Earlier quoted context omitted.
For your future reference, Microsoft offers virtual machines of XP, Vista, and 7 for browser compatibility testing. They expire after three months, but for your uses, they're fine. You'd just grab the VHD out of the VM and use any of the import tools to convert it to your preferred VM format. http://www.microsoft.com/en-us/download/details.aspx?id=1157...
I've used these VMs and they are so infuriating I also want to just buy a full license. They're never able to validate, so they always nag you about "is your windows genuine?" (well I downloaded it from MS so I should hope so!) and shut down every half an hour. They're more trouble than they're worth.
Note: You may be required to activate the OS as the product key has been deactivated. This is the expected behavior. The VHDs will not pass genuine validation. Immediately after you start the Windows 7 or Windows Vista images they will request to be activated. You can cancel the request and it will login to the desktop. You can activate up to two “rearms” (type slmgr –rearm at the command prompt) which will extend the trial for another 30 days each time OR simply shutdown the VPC image and discard the changes you’ve made from undo disks to reset the image back to its initial state. By doing either of these methods, you can technically have a base image which never expires although you will never be able to permanently save any changes on these images for longer than 90 days.