Windows XP Tweaks

The Explorer program (%systemdrive%\program files\internet explorer\iExplorer.exe) creates the familiar Windows interface, but you can use this setting to specify an alternate interface. If you enable this setting, the system start the interface you specify instead of Explorer.exe.
To use this setting, copy your interface program to a network share or to your system drive. Then, enable this setting, and type the name of the interface program, including the file name extension, in the Shell name text box. If the interface program file is not located in a folder specified in the Path environment variable for your system, enter the fully qualified path to the file.
If you disable this setting or do not configure it, the setting is ignored and the system displays the Explorer interface.

START > RUN > GPEDIT.MSC > USER CONFIGURATION > ADMINISTRATIVE TEMPLATES > SYSTEM > FIND CUSTOM USER INTERFACE > RIGHT CLICK > PROPERTIES > CLICK ENABLE > FIND AN ALTERNATE USER INTERFACE > OK