USB boot related forums and pages:
http://www.msfn.org/board/forum/157-install-windows-from-usb/
http://www.rmprepusb.com
http://reboot.pro/forum/71-boot-from-usb-boot-anywhere/
Grub4dos related sites and latest files:
http://code.google.com/p/grub4dos-chenall/
http://bbs.wuyou.com/forum.php?mod=forumdisplay&fid=60
http://reboot.pro/forum/66-grub4dos/
USB formatting utilities:
I am replacing windows 10 with windows 7. I already have a bootable iso W7 on the usb that’s inserted. I’m not clear what I have to select on the opening page if I already have the usb ready to go. Can you clarify? Thanks