did you put a straight .iso on a flash drive and thats what you are trying to use? you have to make it bootable, mount the image, extract the files then put them on the bootable drive. i male bootable drives in command prompt
open prompt as admim
type diskpart
list vol
select vol (volume number of your flash drive, not drive letter)
active
exit
this brings you out of dispart but leaves the admin cmd open. leave it open
make a folder in the root of your c drive, extract ths image files to this folder (mount iso, open image, copy/paste contents to root folder)
now copy/paste those files to the flash drive. you need those files in the root folder too, thats why copy/paste x2
command prompt type
cd..
cd..
you should now be C:\ if. not then cd.. till you are. two periods
now type
cd (name of folder you put files in)
like mine would look like
cd pirated windows disk
then type
cd boot
should look like
C:\pirated windows disk\boot
pretend a moment that you flashdrive is E Drive, now type
BOOTSECT /NT60 E:
replace e with drive letter of your flash drive.
nt60 is for windows 7. i dont remeber if its diff for diff versons of windows. i got like a little rememberance of it being differint i think maybe. who knows.
exit out everything. safely eject flash drive and youre good to go. you have the f12 boot menu on right? all these diff bios have diff settings. and ya if efiwhatever need to turn legacy on. possibly turn OFF safeboot. should work now