To completely reinstall Windows 7 from USB drive, I need help!

You want to do a completely reinstall Windows 7 from USB. You can try The "Plug-and-Pray" Method:

1. Fully turn off the computer, remove the power cord for 10 seconds, and then plug it back in.
2. Insert the USB flash drive into the USB 2.0 interface (the black one, not the blue one). (This is the only way that sometimes can bypass driver issues and doesn't require changing settings.)
3. After turning on the computer, immediately press all the function keys continuously and quickly: F8, F10, F11, F12, Esc, Del - press them quickly immediately after pressing the power button, without waiting for prompts.
4. If a boot menu appears, select your USB flash drive.
5. If nothing appears and you are still stuck in a black screen state, it means the computer cannot boot from this USB drive unless the BIOS settings are modified. There is no other solution for this situation; it is a hardware or firmware limitation.

At this point, you have two free options to do, that don't involve BIOS or drivers, but they're not what you asked for:

• Burn a DVD instead: If your computer has a DVD drive, you can burn the Windows 7 ISO to a DVD. DVDs often boot more reliably than USBs on older machines, and you don't need to change BIOS settings if the drive is already set as a boot device.
• Borrow another computer: Create the USB on a different PC using that machine's built-in tool (like Windows 7's own built-in USB tool that comes with the OS—not the Download Tool, just the native one). Sometimes a different PC creates a more compatible USB for completely reinstall Windows 7.