I had a problem on a very old Windows 2010 server and I got precedent error and no boot way was available:
"c:windows\system32\config\" missing or corrupted
I tried several procedures:
- Last configuratioin restore
- Windows recovery mode.
- Boot from Server CD and going on recovery console and running Chkdsk command
The only solution was to follow this microsoft article:
KB269075
I am focusing on more important commands used:
cd system32\config
ren system system.old
ren system.alt systemalt.old
To copy the default System hive, type the following command, and then press ENTER:
copy c:\winnt\repair\system c:\winnt\system32\config
To copy the System hive that was backed up the last time that you ran the Emergency Repair Disk Wizard, type the following command, and then press ENTER:
copy c:\winnt\repair\regback\system c:\winnt\system32\config
In my case there was c:\winnt\repair\system.bak file that I copied with this command:
copy c:\winnt\repair\system.bak c:\winnt\system32\config
