That also works well for a variety of other things like writing GParted and live distros to flash drives as well while the MS is a bit limited lacking a format option.
Oh yes sometimes you have to use the format option in the UltraISO program as well to prep it for the write. But that can also be used to extract and then write the setup files from the 7 install dvd to the flash drive making that the bootable installation device.
W7 Ultimate x64/W10 Pro x64/W11 Pro Triple Boot - Main PC W7 Remote PC Micro ATX W7 Pro x64/W11 Pro
CPU
AMD Phenom II X4 975 Deneb 3.6ghz - 965 2nd remote pc
Motherboard
Gigabyte GA-790XTA-UD4-Gigabyte GA-880GM-D2H remote pc
Memory
Kingston Hyper X DDR3 1600 1.5v 16gb - Hyper X Fury 8gb 2nd
Graphics Card(s)
MSI HD Radeon 5750 1gb - MSI HD Radeon 6450 on mini tower
Sound Card
Creative Labs X-Fi Xtreme Audio P - Realtek onooard 2nd case
Monitor(s) Displays
ASUS VW199T-P 19" HP 2082a Main-HP 2082a 20" remote pc
Screen Resolution
Asus 1440x900 - HP 1600x900
Hard Drives
WD Black 1TB HD per OS W7, W10, and pending W11 presently on 500gb OS Drive - Pending Triple 1TB HDs for Spanned Storage/backup volume
Single 2TB external USB enclosure, single 1TB System 7 Host/Boot drive, Pending 8TB external HD for system image b
PSU
Corsair 750TX - primary / Corsair CX600 - second
Case
Antec 900-2 - SSD compatible / NZXT Vulcan mini tower
Did you set the USB drive to boot first in BIOS setup? It is normally listed under Hard Drives. Needs to be plugged in to be detected during setup.
Also enable USB support in BIOS. WHile there, check that you have latest BIOS version which should be posted on the SUpport Downloads webpage for your model computer.