SYMPTOMS

You are setting this registry value so that you can see a custom welcome screen background:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background]

"OEMBackground"=dword:00000001

However, this registry key resets back to zero after you click, select or create a different theme in the "Personalization" control panel, hence the custom background no longer shows.

CAUSE

When you change the theme in the personalization control panel, it will change OEMBackground to match the value stored in the theme ini file.

RESOLUTION

Windows 7 has new Group Policy options to control it. Please use the following steps to enable custom welcome screen background:

1. Run "gpedit.msc" in a command window.

2. Navigate to "Computer Configuration" -> "Administrative Templates" -> "System" -> "Logon".

3. Enable the policy "Always use custom logon background".

REFERENCE:

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http://social.technet.microsoft.com/Forums/en-US/w7itproui/Thread/8DFF1F0E-0F89-401C-9DA3-BB251BEE2C46

http://social.technet.microsoft.com/Forums/en/w7itprogeneral/thread/911ac246-3196-41fa-ac7a-0227910985ad

http://social.technet.microsoft.com/Forums/en/winserverGP/thread/d6b199fd-4fd7-4953-88ac-da9940cd84c8

http://social.technet.microsoft.com/Forums/en/w7itproui/thread/2c6973cf-0800-4661-a2c4-2d783a316b01

http://social.technet.microsoft.com/Forums/vi-VN/configmgrosd/thread/bd3f59af-2419-4f23-ad5a-609393d01c39

http://social.technet.microsoft.com/Forums/en/winserverGP/thread/5da565dd-86d1-4f98-8452-b4dbc7441b3e

http://social.technet.microsoft.com/Forums/en/w7itproui/thread/5dc99b7c-17a8-42b1-86b4-0084ffb25a99

http://social.technet.microsoft.com/Forums/fr-FR/win7fr/thread/fe7c1096-61d8-4d1c-8878-822a65fe30f9

http://social.technet.microsoft.com/Forums/de-DE/w7itprogeneralde/thread/8f8cfb3d-6d7b-4d53-bca0-8ae373399e74