As you likely know, unlike its successor, none of the Windows 7 editions allow you install Windows 7 on a USB flash/hard drive and then boot Windows 7 from the USB. For the uniniated, installing Windows from a USB is completely different from installing Windows on a USB. In the first scenario, we use the USB as a bootable media to install Windows, and in the second one, we install Windows on to a USB drive and boot Windows from it.
If you want to install Windows on a USB flash drive or USB hard drive, this is the easiest way to install Windows 7 on USB and boot from it. You don’t need to download complex scripts or execute commands in order to install Windows 7 on to USB.
In this guide, we’re going to show the easiest way to install Windows 7 on a USB flash drive or USB hard drive and boot Windows 7 from it.
Things you need:
# Windows 7 ISO image file (32-bit or 64-bit)
# WinToUSB (check Step 2 for download links)
# 16GB+ USB flash drive or hard drive (8GB drive should do fine but can’t confirm)
Installing Windows 7 on to USB flash drive or hard drive
Step 1: Kick start the procedure by connecting your USB flash drive or hard drive to your Windows 7/8 PC. Please backup all data before continuing further, as the drive will be erased.
Step 2: Next step is to download WinToUSB software by visiting this official page. WinToUSB supports both 32-bit and 64-bit Windows 7/8. Run the downloaded setup file and then follow the straight-forward on-screen instructions to complete the installation. You can install WinToUSB either on Windows 7 or Windows 8.
Step 3: Launch WinToUSB software. On the home screen, click the button next to ISO file box to browse to Windows 7 ISO image file and click OK button to open it. And then select the edition of Windows 7 that you would like to install on the USB.
Click Next button to proceed to the next step.
Upon selecting the USB drive, you’ll see a warning dialog with “Selected device needs to be formatted. Are you sure you want to continue?” message. Click Yes button to continue.
Step 5: Finally, you’ll be asked to select the system partition as well the boot partition on the USB drive. If you haven’t partitioned your USB drive, you can simply select the same partition (full drive) as system partition as well as boot partition (refer the picture). And if you have two or more partitions, please select a partition to use as boot partition and then another partition with at least 16 GB of space as system partition.
Click Next button to begin installing Windows 7 on to the USB drive. This process might take hours depending on your USB drive’s speed and overall system performance. That’s it!
In order to boot from this bootable Windows 7 USB, you need to enable boot from USB feature in the BIOS/UEFI.