Need advice. Black screen in Server 2012R2.

I've got a virtual machine (Hyper-V) running Server 2012R2 with SharePoint 2013.

It's not the end of the world if SharePoint ends up being like exchange for me: about once a year or so I end up building a new server and migrating everything because the old one developed weird unfixable issues.

This machine boots up normally but never displays any video. I get a black screen and a mouse pointer.

Everything is actually running, I can connect to the SharePoint websites, connect with RDP (black screen there too), manage it remotely (everything except device manager).

Advice what to try next, is it possible to fix this?

 

Just to clarify what you're suggesting. I've read about it plenty but never actually done it.

You are saying I need to shutdown the VM, mount the VHD to another working VM, and use DISM from there to repair the offline image in that VHD. Then unmount it and startup my original VM again. Is that about right?

 

Took the machine offline, mounted the VHD as "G:" in another machine. What am I doing wrong?

Code:

C:\Windows\system32>dism /image:g:\ /cleanup-image /restorehealth

Deployment Image Servicing and Management tool
Version: 6.3.9600.17031

Image Version: 6.3.9600.17031

Error: 87

The cleanup-image option is unknown.
For more information, refer to the help by running DISM.exe /?.

The DISM log file can be found at C:\Windows\Logs\DISM\dism.log

 

Should have mentioned I tried that already.