I am using the free 15 day trial from the Parallels website. I installed it fine on my Mac, and began running the Windows XP setup. It got 5 minutes into the setup and asked me to inset an XP Disk...which I did (Windows XP Professional Upgrade). It said It couldn't read the CD and it wasn't valid. Is it because it is an upgrade CD? What CD should I use instead? I have so much software I get confused! Thanks in advance.