Create Boot able USB first you need Windows 7 ISO image , Download official Windows 7
and you have downloaded Window7 ISO file you Can than follow these instructions for how to create bootable Windows 7 USB Drive.
1. The USB needed to at least 4GB in Size.
2. The Windows 7 USB / DVD Download tool is an official freeware tool Microsoft that allows you to installed Windows 7 .
.3 After you have downloaded above windows 7 usb tool Now follow the below steps,
4.Open the Tool from your program
6 Select Windows 7 iso file and click on open Button
7. Now Select option usb your USB Drive
8. After you Selected USB Drive latter ( E,G,H,or I) and than click Begin copying
9. after presses is completed the USB is now Bootable turn off your computer plugin USB.
10 . Now Turn on your PC and Boot from USB.