[Start] [Run] [Regedit]
Registry Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.
Data Type: REG_DWORD [Dword Value] // Value Name: PowerdownAfterShutdown
Setting for Value Data: [0 = Disabled / 1 = Enabled]
Exit Registry and Reboot
 

Note: Whatever text you enter as the value data will be preceded by:
Windows Media Player provided by, so if I had entered text of [TechSupersite], it would read:
Windows Media Player provided by TechSupersite
Exit Registry and Reboot

Enable/Disable Task Manager
This tweak disables user access to Task manager. It must be applied on a user by user basis

[Start] [Run] [Regedit]
Registry Key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.
Data Type: DWORD Value // Value Name: DisableTaskMgr
Setting for Value Data: [0 = Enabled (Default) / 1 = Disabled]
Exit Registry and Reboot

Force New Internet Explorer Window for Launching Shortcuts
By default, when you click a web link in an internet aware program, and there is already an Internet Explorer window open, the web page appears in the open browser window instead of opening a new window. This tweak prevents the new link from being displayed in the existing IE window by forcing an additional IE browser instance to open.

[Start] [Run] [Regedit]
Registry Key: HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.
Data Type: DWORD Value // Value Name: AllowWindowReuse
Setting for Value Data: [0 = Do Not Reuse Window / 1 = Reuse Window]
Exit Registry and Reboot

Show Computer and Username on Desktop (Windows XP)
By Default the "My Computer" icon on your desktop is called "MY Computer". What this tweak will do is name it according to the user logged in and the computers name
[Start] [Run] [Regedit]
Registry Key: HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}  
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.

Next search for "LocalizedString" in the right hand panel, right click on it and select "Rename". change name to "LocalizedString.old". 

Right click on blank white area in right panel and select "NEW" then left click on "REG_EXPAND_SZ" or "EXPANDABLE STRING VALUE". Name the new string value in right hand panel as "LocalizedString". 

Now to set the value, double click on the string value and set it's value to :

"%USERNAME% on %COMPUTERNAME%" 

for just username then use "%USERNAME%"

for just computer name then use "%COMPUTERNAME%"

Exit Registry and Reboot

Disable XP Balloon Tips
A surprising number of folks love the sugary new Windows XP interface, with it's colorful windows and menus. One of these features that's new to XP is the pop-up balloons to let you know that a tour, or hotfix, or network connection (etc.) is available. If you find these simply annoying, you can add the following Registry entry to kill them off for good.

Hive: HKEY_CURRENT_USER
Key: Software\Microsoft\Windows\ CurrentVersion\Explorer\ Advanced
Name: EnableBalloonTips
Data Type: REG_DWORD
Value: 0

If you later decide that you want the balloons back, you can delete the entry, or set its value to 1.