Here?s a quick and easy way to modify the display of the text "My Computer" on your desktop to show the current logged on user and computer name:  

1. Start the Registry editor (regedt32.exe)
   
2. For NT 4.0 move to:
   HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}\EnableExtensions

   A value of REG_DWORD 1 enables and 0 disables this display.
   
   For W2K move to:
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}

   Note: If this entry does not exist, go to the desktop, select My Computer, hit F2 and Type ?My Computer? This action will create the entry in the registry.
   
   
3. Select the <No Name> value and delete it.
   
4. From the Edit menu select Add Value
   
5. Leave the value name blank and set the type to REG_EXPAND_SZ
   
6. Click OK and enter the text:
   User: %USERNAME% on: %COMPUTERNAME%
   Click OK
   
7. Click on the desktop and press F5 (for refresh) and the change takes effect
   

   Note:  Without changing the value type to REG_EXPAND_SZ the %username% and %computername% variables do not get expanded into the actual user name and computer name.