A virtual machine that you create from a physical machine prompts you to activate Windows when you use it in Workstation Pro.
After you create a virtual machine from a Windows Vista or Windows 7 physical machine, or from a physical PC that came with Windows preinstalled, you were required to reactivate Windows in the virtual machine.
When you create a virtual machine from a Windows Vista or Windows 7 physical machine, the operating system detects that the computer hardware has changed. When you make a significant hardware change, Microsoft requires you to activate Windows again.
The OEM versions of Windows that are preinstalled on some new computers are customized for those computers. OEM licenses of Windows are not transferrable.
Any virtual machine that was created from a physical machine that had its Windows license key successfully activated needs to be reactivated when you run it in Workstation Pro.
The activation process in Windows Vista and Windows 7 is different from the Windows XP activation process. In Windows 7, retail activation keys are good for only one use. If you enter the same activation key in Workstation Pro that you used previously, you cannot successfully activate the virtual machine.
The activation wizard tells you that the activation key was already used and prompts you to call the Microsoft activation hotline to get a second key. If you did not previously call the hotline for the same license key, you should receive a new activation key. Your call is not transferred to an operator unless you call repeatedly for the same key.
See the Microsoft Web site for more information about why reactivation is necessary.