Locked Windows using Group policy - how to revert back?

I have changed the security settings in Group Policy Editor. That was not a good idea!
Can anybody tell me how to reset the settings in Group policy to the default values? (It must show: 'Not Configured" for each object)
My computer's not connected to the internet or a server allthough, Windows XP Pro was installed with a server.

 

Steve,
I cannot open the RUN command. I allso cannot use System Restore. I think it's because I have changed the USER ACCESS RIGHTS in GPEDIT.
Maybe I can open GPEDIT with a program like WORDPAD?

 

I also disabled Control panel with GPEDIT.MSC.
I cannot use Control Panel or System Restore or the Run Command to open GPEDIT.MSC.
I've found the following in MSDN but I cannot open the %systemroot% - blocked by Group Policy....

To reset the user rights for the default Domain GPO:
1. Backup the GptTmpl.inf file in the Default Domain GPO folder of the Sysvol. Mine is located at:
%SystemRoot%\sysvol\sysvol\<Domain Name>\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\MACHINE\Microsoft\Windows NT\SecEdit\GptTmpl.inf.
2. To reset the user rights to the default settings, replace the existing content of the [Unicode], [System Access], [Kerberos Policy], and [Version] sections of the Gpttmpl.inf file with the content listed below. You MUST remove the [Privilege Rights] section and entries. You may elect to retain the [Event Audit] and [Registry Values] sections, if they are present, and represent the desired settings.
Default Domain GPO Settings:
[Unicode]
Unicode=yes
[System Access]
MinimumPasswordAge = 0
MaximumPasswordAge = 42
MinimumPasswordLength = 0
PasswordComplexity = 0
PasswordHistorySize = 1
LockoutBadCount = 0
RequireLogonToChangePassword = 0
ForceLogoffWhenHourExpire = 0
ClearTextPassword = 0
[Kerberos Policy]
MaxTicketAge = 10
MaxRenewAge = 7
MaxServiceAge = 600
MaxClockSkew = 5
TicketValidateClient = 1
[Version]
signature= "$CHICAGO$ "
Revision=1
3. After making the changes, you must increment the group policy version by opening the Gpt.ini file at
%SystemRoot%\sysvol\sysvol\<Domain Name>\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}. It is best to multiply the version by 10 to insure it does not become outdated before the policy can be applied.
4. Save and close the Gpt.ini file.
5. Apply the new group policy by running secedit /refreshpolicy machine_policy /enforce

 

Group policy

Yes, you are right...

From now on I'll be more carefull.

 

Yes.
My account, (administrator account), and a user account (limited). I've tried F8 when the PC starts. All of them gave the same result

 

Group policy

I've done it! When fooling around trying to open GPEdit I remembered the shortcut on the Administrators desktop and luckily it opened GPEdit.
The User Configuration: Restrict software access was enabled. It won't change when I try to disable it.
Sitting there staring at my PC, (I LOVE AND HATE it), I thought when something is not present, it can't do anything, so if that setting is not present what should happen?
I hit DELETE on that setting and prayed that the PC will work again.
Thank goodness, when I restarted my PC everything was back to normal.
System Restore work again, so I restored my system to an earlier time.
Everythings working fine now, thank you Steve for trying to help with this thread.