This is not for your benefit. This is for mine. If you happen to find it useful, that’s nice. Feel free to send me questions if you need help.
- Create a single NTFS partition on the thumb drive.
- (If you’re using a physical install DVD) put the DVD into the drive and mount it or (if you’re using an ISO) mount the ISO as a loopback device.
- Copy all of the files from the DVD or ISO to the thumb drive.
- Install ms-sys.
ms-sys -7 /dev/sdxto add a bootloader to /dev/sdx, which should be substituted for the actual block device name of your thumb drive.
- Unmount everything. You now have a functioning Windows 7 install usb.