If you have installed the Windows Vista Beta 2 version, and it did not activate automatically, a dialog will appear that says “Activate Windows now”. You are presented with four options, which are: Activate Windows Online Now, Retype your product key, Show me other ways to activate, and Buy a new product key online. If you select any of the first three, you will get the error code.
3 things you should do if Authentication failed
This is caused by a bug in Beta 2 in the User Account Control security settings. Select ‘Buy a new product key online” just to verify that the browser opens to a Microsoft product key page. Then restart the PC in safe mode. Click on the Administrator account and enter the password you gave during setup and login. Click start, right-click Computer, and select Manage. Click the plus sign by “Local users and groups” to open the folder, and click “Users”. Right-click Administrator. Click Properties, and de-select “Account is disabled” box.
Then you must edit the registry by running Regedit. Go to the key:
If SpecialAccounts does not exist, then you need to create it. Then create the UserList key. Select UserList on the left pane, then right-click in the right pane. Select New – “DWORD (32bit) Value”, Value name: Administrator, Value Data: 1. Click OK, and then restart your system. You will then be in the Administrator account, so log on as administrator. Then you will see the “Activate Windows now” dialog, and click Activate now.
TipFor more information, please see: How to fix User Account Control error #0x800705b4