Settings to Enhance Functionality
WARNING: This article contains information about editing the registry. Before you edit the registry, you should first make a backup copy of the registry files (System.dat and User.dat). Both are hidden files in the Windows folder. Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows. Use Registry Editor at your own risk.
Enable Command Line Completion (Windows NT) Cool!
Command completion allows you to type only a portion of a file name, and then have the system complete the rest by pressing the TAB key. This is similar to the the UNIX shell command completion feature. 
1. Open the key below and change the value of "CompletionChar" to "09" for the TAB key. 
2. Exit and reboot your PC. 
Now when you type the first part of a filename, and press the TAB key and Windows will complete the filename for you. 
Note: Changing the value of 'CompletionChar' changes which key executes command completion i.e. '09' is the TAB key. 
Registry Settings: 
Key: [HKEY_CURRENT_USER\Software\Microsoft\Command Processor]
Value Name: CompletionChar
Data Type: REG_DWORD
Data: 09 = enabled (TAB Key)

Changing the Default State of the NUMLOCK Key (Windows NT)
The NUMLOCK key is usually only turned on before the user has logged into the computer, this can cause problem for people with portable computers that do not check the status of the NUMLOCK key before typing their password. The default behaviour can be changed with this setting. 
1. Open your registry and find the key below. 
2. Change the value of 'InitialKeyboardIndicators' to either '0' for off, or '2' for on. 
Note: This change will affect all users but value can also be changed on a user basis by modifying [HKEY_CURRENT_USER\Control Panel\Keyboard] and the same registry key.
Registry Settings:
Key: [HKEY_USERS\.DEFAULT\Control Panel\Keyboard]
Value Name: InitialKeyboardIndicators
Data Type: REG_SZ
Data: 0 = NUMLOCK off, 2 = NUMLOCK on
More info: http://support.microsoft.com/support/kb/articles/q170/9/03.asp

Create a Useful Name for My Computer
This tweak makes it simple to determine which computer you are logged on to and who you are logged on as. Using this tweak will rename "My Computer" to "Username on Computername".
Using REGEDT32.EXE (this is necessary for REG_EXPAND_SZ) open your registry and find the key below.
Key: HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}
Value Name: (Default)
Data Type: REG_EXPAND_SZ
Change the value of (Default) to equal "%USERNAME% on %COMPUTERNAME%".
Exit the registry editor, click on your desktop and press F5 (for refresh). The "My Computer" icon should now be rename to "Username on Computername".

PC PowerDown after Shutdown in NT
Win9x has a niffty feature where the PC powers down after a shutdown. This new capacity requires an ATX power supply. You
can get similar functionality in NT:
Hive: HKEY_LOCAL_MACHINE
Key: Software\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: PowerdownAfterShutdown
Type: REG_DWORD
Value: (0 = disabled, 1 = enabled)
After this, the shutdown dialog should be Shutdown and Power Off.
If you make the registry change and the PC reboots instead of powering down, you can often get it to work by upgrading your
hal.dll with the Softex dll which shipped with SP4.
     cd %systemroot%\system32
     ren hal.dll hal.dll.original
     copy cd_drive\i386\hal.dll.softex hal.dll
If this does not work, and your PC just reboots, check with the vendor of your PC and see if they have a powerdown BIOS and
hal.dll. It may be, that you do not have an ATX power supply. Newer PCs do, but ...

Add Your Own Tips (Windows 9x and NT)
Are you sick of seeing the same tips again and again when you first logon to Windows? Now you can change them to whatever you want, whether it's quotes, jokes or a to-do list, anything is possible.
Simply open your registry and find the key below.
Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Tips
Data Type: REG_SZ
To create a new tip, click on Edit | New | String Value and name the value by incrementing the existing values. Double click on your newly created entry and enter any text you want.
To delete, simply highlight the enter and either hit the <Delete> key or choose Edit | Delete