If you like the command line then you can use these steps:

1. diskpart
2. select disk 1 (or whatever number it happens to be on your system. Type “list disk” from within the diskpart command to find out)
3. clean
4. create partition primary
5. select partition 1
6. active
7. format fs=fat32
8. assign
9. exit

2. Now insert the Windows 7 DVD into your drive, or mount the ISO file using your favorite tool and copy the contents of the drive to the USB Flash Drive.

Again, command line instructions are here as well…(this command assumes D: is your DVD-Drive and E: is the Flash Drive — change them as required.

xcopy d:\*.* /s/e/f e:\

3. Now you can boot off the USB drive (you might need to enable USB booting in your BIOS) and install Windows 7 in the fastest possible time.