Your USB 3.0 ports are not recognized. Use a USB 2.0 port, or slipstream USB 3.0 drivers into the ISO using tools like NTLite before creating the bootable USB.
Many users upload "Official ISO" images to the Internet Archive. You can search for "Windows 7 Ultimate 32-bit ISO" there. Since these are community uploads, ensure you verify the SHA-1 hash of the file against known official Microsoft hashes to ensure the file hasn't been tampered with. download windows ultimate 7 32 bit
If you are looking to download it, here are the most reliable ways to proceed: Your USB 3