CNET posted a news story that Parallels is likely to cause users to violate Microsoft's licensing terms
Parallels, known for using virtualization to solve consumer problems, thought it had a surefire new use for its technology.Microsoft warns on Windows 7 upgrade tool
Why not use the same approach it used to put Windows on a Mac to help ease the move from XP to Windows 7. The solution was elegant, helping users both make the move and even run older programs that weren't compatible with the new version of Windows. At first, the signs from Microsoft were encouraging; the company even invited Parallells to a Windows 7 momentum event in Paris to publicly talk about the program, Parallels Desktop Upgrade to Windows 7.