If your work computer gets mobbed with people and you need to stop others from using it here is nice trick that may help you.

What’s The Catch ?

Well the logic is simple. Whenever you PC starts it looks for the boot device in BIOS. By default your hard disk is assigned as the primary boot device. Once the device is found the computer looks for the boot.ini file which contains the necessary boot information. So if you can somehow remove/rename the boot.ini file and replace it within your USB you can possibly use the USB as the passkey to boot your PC.

Things you will need

1. This trick works for Windows XP.

2. An USB Drive.

3. A PC that supports USB boot.

4. A Windows XP installation disc (in case something goes wrong). :|

Let us get started

1. Configuring Windows XP

At first we will be configuring Windows XP installed on your PC. Follow the steps below and do exactly that is instructed.

1. Open Windows Explorer(Winkey + E) and go to your installation directory i.e the partition where your Windows XP is installed. Go to Tools > Options > View(Tab).

2. Now scroll down until you find the options as shown in the screenshot below. Check/uncheck those as shown in the screenshot. Once done, save the changes by pressing Apply and then OK button.

3. As the hidden system files gets displayed, you will find the files

• boot.ini
• NTDETECT
• ntldr

4. Now copy those files to a freshly formatted USB drive that you will be using to lock your PC. Once the copying is done just remove your USB drive.

5. Skip this step and go to the following section, “Configuring Boot Priority in BIOS“. We will return here once again after we are done configuring the BIOS.

6. Now rename the boot.ini file as boot.ini.bak. This will ensure a backup of the original boot.ini file which can be used if you need to revert back.

7. Proceed to the third and final section, “Test Drive“.

2. Configuring Boot Priority in BIOS

Restart your PC and press [F8] key to go to your BIOS settings. Though for some PCs [F2], [F10] keys are also assigned for getting into the BIOS settings. If you are not sure of the exact key, you may try consulting your hardware manual which you got while buying your PC.

So now that you are reading this line, I will consider that you know how to enter your BIOS and also know how to configure it. Follow the steps afterwards.

1. Go to the Boot menu to change the Boot priority.

2. Assign your boot priority such that the primary boot device is USB disk and the secondary boot device is hard disk.

3. Now save the changes and exit from the BIOS settings. In most cases the [F10] key is assigned for the operation “Exit saving changes”.

Okay now that we are all set, we will be restarting (without the USB inserted) the PC and booting as usual. As told earlier return back to step #6 of the previous section.

3. Test Drive

Step#1. Restart your machine without your USB drive inserted, if you have done everything as instructed your PC will throw a boot error. This means the boot.ini is properly renamed.

Step#2. Now insert your USB drive and restart(Ctrl+Alt+Del) your machine again. Now you will see that, the PC boots completely alright as it did earlier. This infers that the BIOS is set exactly and detecting your USB device as the primary boot device and the boot.ini file located within it is working properly.

Well that is all. Now every time you need to use your PC you will have to use that USB drive and at the same time others who don’t have the USB device will not be able to start your PC.

How to Revert Back

If at any point of time you need to revert back, just boot your Windows using the USB drive and then go to the Windows installation drive and rename the boot.ini.bak file to boot.ini. There is no need to change the BIOS boot priority settings. Now all done, remove your USB drive and restart your PC without inserting it.

What if You have Screwed Up everything ?

Well operating systems and hardwares are pretty notorious at times and behave in an unexpected manner. It may happen that though you have followed all the steps properly your PC doesn’t boot at all. Well do not panic, you will just need to repair your Windows XP once. Follow Microsoft’s guidelines on how to repair Windows XP.

If you are facing some problems regarding the trick, feel free to ask via comments.