How to Create a Bootable USB Flash

By Jonathan Langdon

A bootable USB flash drive provides a convenient means for installing and repairing Windows. Turn on a computer with the USB flash drive inserted and Windows setup can be accessed without a disc. A USB flash drive is both durable and portable. Where a CD or DVD must be secured in a plastic case or risk breaking, a USB flash drive can be carried around in a pocket without worry. Creating a bootable USB flash drive is worth the tricky process of making an ISO image then joining it to the device using free programs.

Things You'll Need

  • BIOS set to allow booting from USB
  • WinZip software
  • USB flash drive with at least 4 GB capacity
  • Windows installation disc

Creating the ISO Image

Step 1

Visit and click “Freeware” in the left-side navigation menu. Locate “LC ISO Creator” in the list of freeware tools and click “Download.” The file is labeled “”

Step 2

Insert the Windows installation disc into the disc drive of the computer. Close any windows that appear as a result of the Windows auto play feature.

Step 3

Open the “LCISOCreator” ZIP file and extract “LCISOCreator.exe” to a new folder. Make sure the program is easy to find.

Step 4

Run “LCISOCreator.exe.” ISOCreator is set by default to create an ISO image from whatever disc is in the computer's disc drive. Click “Create ISO.” Name the ISO, choose a location where the ISO will be saved and then click “Save.” LCISOCreater will begin creating the ISO image of the disc. Once all of the squares in LCISOCreator have turned red, they will become gray again. The ISO is ready.

Joining the ISO Image to the USB Flash Drive

Step 1

Insert the USB flash drive then copy its contents to a folder on the computer. The USB flash drive must be formatted and all data on it will be lost.

Step 2

Open the “Start" menu then select “Computer” (or “My Computer”). Right-click the USB flash drive then click “Format” in the menu. In the new Format window, set “File system” to “FAT32,” then make sure the square next to “Quick Format” in the “Format options” section is checked off. Click “Start” to begin formatting the USB flash drive. Click “Close” when the process is complete. Note the letter assigned to the USB flash drive.

Step 3

Visit the SourceForge website (link available in the Reference section) and type “unetbootin” into the “Enter keyword” field. Click the “Download Now” link in the listing for “UNetbootin, Universal Netboot Installer.” UNetbootin does not have to be installed.

Step 4

Run the UNetbootin program. In the window for UNetbootin, select “Diskimage” next to the button labeled “ISO.” Click the icon marked by three dots at the end of the text field to open the “Open Disk Image File” window. Search for the Windows ISO image created in the “Creating the ISO” section, click the file to have its name appear in the “File name” field and then click "Open." The “UNetbootin” window will return to the forefront.

Step 5

Set “Type” to “USB Drive” then select the assigned letter for the USB flash drive next to “Drive.” Click “OK” to join the Windows ISO image to the USB flash drive. UNetbootin will present the options to reboot the computer or just exit the program once the process is complete.

Tips & Warnings

  • A bootable USB flash drive can be used to set up multiple computers provided enough product keys are available.
  • Problems with a USB flash drive can usually be fixed by formatting it.
  • offers programs for multiple operating systems.
  • Not all motherboards allow booting from a USB.
  • The USB flash drive must be formatted again to remove the ISO image.
  • There is a chance that the USB flash drive can become damaged during the process of turning it into a bootable drive.
  • Distributing ISO images of Windows without a license is a violation of copyright.