1) Make a new account and simultaneously make it a local admin.
2) Turn an existing account into a local admin.
This is very easy, and can be done at school. THIS WILL NOT MAKE YOU A NETWORK ADMIN! It will only make you an administrator on that computer.
Step 1: Make a New Account, and Make it an Administrator.
net user USERNAME PASSWORD /add
net localgroup administrators USERNAME /add
This is what you just typed means:
@echo off: This makes the file look more professional. It is purely superficial.
Everything else is pretty easy to figure out. If you have trouble with it, goto [http://www.instructables.com/id/Batch-Files-Some-basics...../ this Instructable]. Save it as a batch file. To do this, save it into a folder with some random name with .bat at the end. Where it says Save as type:, click on the drop-down menu and select All types. Look at one of the pictures below to see an example.
Now, we need to configure this file. Replace the word USERNAME with a username. It needs to be the same in both places. Replace PASSWORD with a password.