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To start, lets open up a command prompt (Start > Run > cmd > PRESS ENTER).
At the prompt, enter the following command but replace 15:25 with 2 mins after current system time
CODE
at 15:25 /interactive "cmd.exe"
(dont forget to replace 15:25 with 2 minutes after current system time)
at the time set a new CMD box will magicaly appear
You'll notice that the title bar has changed from cmd.exe to svchost.exe (which is short for Service Host)
close the first CMD box but leave svchost open
now press CTRL+ALT+DEL, In task manager, go to the processes tab, and kill explorer.exe; your desktop and all open folders should disappear, but the system command prompt should still be there.
in the command prompt that remains type explorer.exe
A desktop will come back up, but what this? It isn't your desktop. Go to the start menu and look at the user name, it should say "SYSTEM". Also open up task manager again, and you'll notice that explorer.exe is now running as SYSTEM. The easiest way to get back into your own desktop
You are now the God of the windows machine
Abnormalities & experimentation
I've noticed different results depending on the service pack and hot fixes installed; for example, sometimes when I try to open the user control panel applet, I get a error saying user not recognized, and the location where the Local System account profile is stored also varies. I haven't had much time to explore this, so if you find anything else, please use the email address found in the contact section of this article, and send a note my way.
A quick fix
A way to prevent this from happening at all, would be to make the task scheduler service run under a unprivileged account. You can do this by opening the services control panel (Start > Run > services.msc), and right clicking "Task Scheduler" and going to the Log On tab. Change it to "This Account" and enter the account information you want it to use (has to be an existing account) then restart the service. This may break some programs that use the Task Scheduler and depend on it for SYSTEM access; you have been warned. Otherwise, simple disable the Task Scheduler service.

