Moving Windows 7 Licence to Virtual Machine

I have bought a new computer with Windows 7 Pro pre-installed on it. As I need to use Linux I have used this tool Advanced token manager to backup my product key. Then I have replaced the OS with Linux so I can then install my Windows 7 back again within the primary Linux OS as VM but I wasn't able to use the same product key as getting the error 0XC004E003.I'm not sure about the licensing system for MS but it looks to me as MS still thinks that the Key is being used on a different machine and I'm not sure how to change this. Any help would be appreciated.