winver was not recognized when run from the command prompt in recovery and diagnosis mode!!!
Note the drive that you are working under in that circumstance. X: is a virtual drive implemented by a RAM disk and it only contains a small subset of the normal commands. But if you knew where (what drive letter) your \Windows\System32\ was perhaps you could try executing its winver.exe. FWIW I just tried simulating some of that by killing explorer.exe and using Task Manager's File New... command to start winver.exe. So that at least proves you don't need to have explorer.exe running to do it.
Also, supposedly there is a PowerShell we can use from where you are so let's see if there is a query you can do with it which would be equivalent to winver...
Heh. I thought it was going to be $PSVersionTable for its BuildVersion element but that is not up-to-date! How helpful.
Here it is just in case it ever does get in synch:
$PSVersionTable | out-string -stream | sls "BuildVersion"
Actually I suppose that could be even worse in that mode anyway, showing whatever BuildVersion is present in the PowerShell that is built into the RAM drive. Oh well. Try just finding the real winver.exe location and then execute it from there.
Good luck
Robert Aldwinckle