Registry: Change the Position of the Desktop Wallpaper (Windows 9x and NT)

Unfortunately Windows only gives you the limited options of center or tile for the placement of the desktop wallpaper. With this setting you can move the image anyway on your desktop.
Open your registry and find the key below.

Key: [HKEY_CURRENT_USER\Control Panel\Desktop]
Value Name: Wallpaperoriginx, Wallpaperoriginy
Data Type: REG_SZ
Data: Distance in Pixels

Create two new string values of 'Wallpaperoriginx' and 'Wallpaperoriginy'. If the values already exist then you simply modify them.
Set the value of 'Wallpaperoriginx' to equal the horizontal offset, and set the value of 'Wallpaperoriginy' to equal the vertical offset. Then either restart Windows, or change your background image through the Control Panel.

Note: The image is offset from the center of your desktop, so you can use positive and negative values.

Registry: Change the Message Shown on the Logon Box (Windows NT)

You can personalize (or legalize) the message displayed on the logon box above the user name and password.
Simply create a new string value named 'LogonPrompt' in the key below, and enter the text you want to display. The default message is: 'Enter a user name and password that is valid for this system.'

Key: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
Value Name: LogonPrompt
Data Type: REG_SZ

Registry: Disable Task Manager (Windows NT)

To enable or disable the user's ability to start Task Manager to view processes, applications running, and make changes to the priority or state of the individual processes, edit following key in registry using 'regedit' program.
(This option was added in Service Pack 2.)

Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]Value Name: DisableTaskMgr
Data Type: REG_DWORD
Data: (0 = disabled, 1 = enabled)