Or *Go to Start menu Accessories, right click on Command Prompt and select Run as administrator. Next type LIST DISK command and note down the Disk number (ex: Disk 1) of your USB flash drive. In case, if you don’t have Windows 7 DVD and have just ISO, you need to use a free software named Virtual Clone Drive. Once you enter the above command you will see the below message. Copy all the Windows 7 DVD contents to the USB flash drive.
In the below screenshot my Flash Drive Disk no is Disk 1. Download Virtual Clone Drive, then use the Virtual Drive letter as you DVD drive letter after mounting the Windows 7 DVD image. Type another command given below to update the USB drive with BOOTMGR compatible code.
/NOB Do not allow an older BIOS to be flashed to the platform. /NOBIOSINFODo not display BIOS date and part number while flashing.
/R=n Retry flashing a block n times if flash fails.
You can also your Win RAR software to extract the Windows 7 ISO file to desktop. Maximize the minimized Command Prompt in the 4th step.