Windows 7 and Server 2008 R2 does not Natively support NVME M.2 Drives, it is recommended to upgrade to windows 10 or later
however if that is not appropriate for your needs at the current time Microsoft has released a limited Hotfix, This hot fix is located at the link below however as Support for windows 7 and server 2008 R2 is ending this hotfix may be pulled by microsoft at any time and the recomended solution is to upgrade to windows 10 or later operating system.