SharePoint foundation 2010 on Windows Server 2012 R2

Hello,

I have done an in place upgrade of my Windows 2008 R2 enterprise server (running Sharepoint Foundation 2010) to Windows 2012 R2 standard (for license reason). I have applied the latest service pack 2 and hotfix (14.0.7113.5000) to sharepoint . When I want to open the SharePoint 2010 Management Shell I am getting "The Local farm is not accessible. Cmdlets with FeatureDependencyId are not registered". I have tried different thing (like setting up a config file for powershell to load version 2,  or running PSConfig.exe -cmd upgrade -inplace b2b -force -cmd applicationcontent -install -cmd installfeatures ) without success.

I am currently unable to make a backup of the farm.

If someone would have an idea, that would help me a lot.

Thanks

PS: I am able to open The Sharepoint Central Administration, and the farm is working.