Can I join my Sever2012R2 HyperV server to a forest that the DC is once of the VMs

I built a forest with 2012R2 DC datacenter, Exchange 2013, and wanted to join my Hyper Vo server to that DC from the workgroup it started from. Now I cannot RDP to the HyperV server. but can the DC. It appears to be in a hung state. Befor I reboot the Hyper Vi server been researching for what the issue may be. I know you need to restart to join a domain. What if the DC VHD is on the server. Maybe the way our of this is to spin up another DC on a another box>