Making a flash drive for Windows 7 requires the following steps. Do you have something that can accomplish them?
Clean the drive to remove configuration data, and diskpart is normally used for this.
Create a partition and format using Fat32, then make it active, assign a drive letter and copy over the files from an Install DVD, or a mounted .iso file.
If you want to use UEFI, you will also need to create a folder in the EFI folder and add a file called bootx64.efi which is a renamed bootmgwf.efi file. So you have EFI\boot\bootx64.efi and that file is on all x64 Windows 7 installs in the Windows\Boot\efi folder or you can use 7 Zip to pull it from the .iso file.
The Microsoft .iso to flash drive utility...