There may come a time when you may want to or need to reset your Windows Security settings to default values. Maybe you messed them while configuring them manually or maybe your PC just recovered from a malware infection. If for some reason you’d like to reset all your Windows 8, Windows 7 or Windows Vista security settings to their default values, you may do so as follows:
Reset Windows Security settings
Open an elevated command prompt and type the following command:
secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose
After you run this, the standard user accounts may no longer appear on the logon screen when you re-start your computer or try to switch users.
This occurs because standard user accounts are removed from the Users group when you reset Windows security settings.
To add the affected users accounts back to the Users group, follow these steps.
Open an elevated command prompt. In the Command Prompt window, type net users and hit Enter. A list of user accounts will be displayed.
For each account name listed in the Command Prompt that is missing from the log on or switch user screen, type the following command and hit Enter.
net localgroup users accountname /add
In Windows 8 | 7 | Vista, the Defltbase.inf file is a Security configuration template for the default security. You can view the settings for this file in the following location:
You will see all changes made, in a newly created log file situated at the following location:
If you don’t want to do it manually, you can simply use this Microsoft Fix it 50198 to let do all this, automatically.
How to Reset Windows Firewall settings to defaults may also interest you.