How to lock your computer using USB stick

If you are tired of people who use your computer without your permission and change anything they like, here is a small trick which will not even allow your computer to boot without a USB stick , which acts as a key to boot your PC. For Windows 7 check the list of tools which I have discussed at the end.

Locking the Boot Process : Understanding what you are going to do

  • When windows boots it checks for the primary boot device in bios which is by default is your hard drive.
  • Then it looks for a system file called as Boot.ini which tells windows where to start booting from. Without this file windows will throw you an error ” Invalid Boot.ini ” or “Windows could not start “

So what this trick does ? . It will make the windows look for BOOT.INI in a USB drive Follow the steps

Make Hidden Files visible:

Boot.ini is hidden file by default. Open C drive and go to Tools > Options > View. Look for Hide Protected system files . Uncheck it. Now you should be able to see the BOOT.INI file.

Copy System Files:

Copy the files 1) BOOT.INI 2) NTDETECT 3) NTLDR to your USB stick. This is assuming that your windows is installed in C drive. In case its D drive look into D drive. Remove the USB stick

Boot Ini in Windows


Setting up BIOS

Now restart your computer and keep [ F8 ] key pressed as soon as the computer starts. After you get into the BIOS, Look for the menu item where you can change your Boot Device. After you find it, set USB device as first boot device and Hard disk as secondary .

Here what we have done is, when you computer starts it will first look for a USB stick to boot from. When it does not find it , it will look for your hard drive. Restart your system now.

Renaming Boot file

Now the main trick starts. Rename your boot.ini file as book.ini.bak. This way you have created a backup file which can be used in case you want to revert back.

Checking the setup

Now restart your system. Don’t insert your USB stick now. If you have done everything fine, you will be getting boot error. If not your BOOT.INI file is not renamed properly.

Using USB stick as key

Now insert your UB stick and reboot. You should be able to see windows loading properly.

That’s all. Now every time you need to load windows you will need to use your USB drive.

What if I lose my USB drive or it fails to work ?

You can make a Windows Recovery Disk or Follow the steps here to revert back. What it does is creates the boot.ini file again and your computer boots normally.

If this feels geeky, Below is the list of applications which you can use to lock your computer :

My Lock :

This program installs in a USB driver and keeps running in the background. If you unplug your USB from computer, it will lock instantly. To unlock you either need to plug the USB or use pass code which is set up during first installation. This makes sure you can still unlock your computer even if you lost your USB. Also make sure you run it with admin privilege.


My Lock Application

Download from here

USB System Lock  :

This application works on similar lines as the above application. It auto detects your USB drive and then creates a key disk. This key disk has a unique value which is checked every few seconds. Once the USB is unplugged, the computer gets locked and there is no way to unlock without it. Download it from here

About Ashish Mohta

A Professional Tech blogger, Editor and Writer who talks about solving day to day problems of people who use computer. His expertise are in Windows 7, Microsoft Office, Software, Mobile Apps and Video Posts.


  1. EY man 😀 Nicely done, I will buy a Seperate USB for this ^^ One who will match my Laptop, But is it possible to lock youre Window Account and unlock it again with a USB? That would be handy 😀 so you can Lock every account with a Own USB Stick for on school.

  2. How to do all this thing on vista?

  3. hi,

    you can use the USB Drive Monitor to lock your PC using your USB as an access key, you can also record logs of files contained on unauthorized USB Drives inserted to your pc up to 3 folder levels deep…….and much more

    try it its free, type “USB Drive Monitor Download” in google.

  4. I know a program that can not only lock and unlock your PC but also helps you automatically log in/out. You will need a USB stick for it and it will act as a car key to your machine. Come-> plug it in -> start work. No need to type in your password. Rohos Logon Key is not just a primitive desktop locker but two-factor authentication solution. You may read more on it.

  5. Nice thinking, that’s a pretty smart way to do it without relying on potentially failing software 🙂
    Just one thing: is there an equivalent for WIndows 7? :/

    Oh, and that Olga character with her Rohos stuff is a spammer, i’ve seen her on dozens of sites already with that same stupid ad, which leads to a non-free program… Care to block her, please?

  6. login windows with usb flash drive –
    support Win7. it is not simple desktop locker. but complette login solution. recommend.

  7. Predator doesn’t work at all. you can walk right through the front door with no password or usb stick

  8. Sweet, thanks.
    Now I just need to buy that USB Lancelot Key 🙂

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