OSX 10.6 admin account missing After a power shortage a Mac with El Capitan installed, downgraded to 10.6 and the admin account is missing.

The main session password is also in an older state, and we cannot connect anymore.
We have tried to suppress the /var/db/.AppleSetupDone and go through the account creation process but without success.

Does anyone have any way to retrieve an admin account?
Try restarting and then press Command+S. This will boot the computer in single user mode. After everything loaded, type in ( /sbin/ mount -uw /)first, then (rm /var/db/ .applesetupdone), and finally (shutdown -h now )or (reboot). This erases the previous setup and makes the mac think its brand new. All you would need is to create a new admin account.