To restart Explorer in order to test a registry setting without a reboot, we usually terminate explorer.exe process using Task Manager. The Task Manager method is like forcibly killing the process instead of terminating it cleanly.

Jeff, a Software Design Engineer at Microsoft posted a great Tip on how to cleanly start and stop explorer.exe in Windows XP.

Windows Vista

Although the above method (originally written for Windows XP) would work for the Classic Start menu in Windows Vista, not everyone use the Classic Start menu. Aaron Margosis of Microsoft tells how to cleanly stop Explorer.exe on Windows Vista if you’re using the default Start menu. This is using a hidden GUI option that’s present in Windows Vista systems.

The GUI option named Exit Explorer shows up when you follow these steps:

Click the Start button. Press and hold the CTRL and SHIFT keys, and right-click on an empty area in the Start menu. You’ll see a Popup menu containing the two options namely Exit Explorer and Properties.

Note that the above Popup menu can be launched by holding the CTRL and SHIFT keys and then right-clicking on the Start menu power button itself.

NOTE After selecting the Exit Explorer command, the shell (Start menu, Taskbar and the Desktop) will the closed and the other applications  continue to run. You need to manually start a new Explorer.exe process by launching Task Manager. Use the CTRL+SHIFT+ESC key sequence to launch Task Manager. From the File menu of Task Manager, choose New Task (Run…), type Explorer.exe and press ENTER.

If you’re an avid Keyboard user:

To launch the above Popup menu using keyboard, use the following key sequence:

Press CTRL+ESC to launch the Start menu.

Press Right-arrow, so that the focus is set to the power button.

Press and hold CTRL and SHIFT keys, and then press the Application key . This key has an image of a mouse pointer on a menu. Depressing this key will display the selected item’s shortcut window. This opens the Popup menu containing the Exit Explorer command. Press the X button on the keyboard to run the command.

Key sequence - Option #1: {CTRL} {ESC} {RIGHT} ({CTRL} {SHIFT}) {APPKEY} {X}

Key sequence - Option #2: {CTRL} {ESC} {RIGHT} ({CTRL} {SHIFT}) {F10} {X}

Perhaps you can try KiXtart or AutoIt to automate the above using SendKeys.