Just do the Following::
Punch in “CMD” at the Run Dialog Box.
There at CMD type in the following::

“at TIME /interactive “cmd.exe””
at whatever time you want usually 1 min after sys time. For example:

“at 8:39PM /interactive “cmd.exe”" (Without the first and last “)

Then close that dialog box by using exit command or using the cross.

At the sechduled time another command prompt opens.

Now,
press CTRL+ALT+DEL to open task manager.
NOW Close Explorer.exe from the process tab.

in the open command prompt dialog type in “Explorer.exe“.

Now You are using the “SYSTEM” user which is even more powerful than Administrator USER.

PS: I got emails asking me how to remove the task, just  go to control panel, then Schedule Tasks, then you will see a file called AT, just delete it.