If you can get into the Safe Mode list of options, then you can restore to the "Last known good configuration".
Instructions for Safe Mode here
I hope that helps.
Mark
we lost access to the OS.
What we did:
1. We changed the properties of the PC
2. We unchecked the domain and checked the group.
3. After reboot the login did not work
4. we do not have any other local account on the PC
5. the account we were trying to login was network account.
TIA

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