Installing Win7

The Boot app wizard asks you to choose the iso image you wish to burn to the USB storage disc, but where is it on the WIN7 installation disc.
I cannot see an iOS file on it, but it must exist. Does it have a different file type?

 

All went swimingly up to the point of the os actually loading at which point it has frozen for 2hours at "Windows is loading files............."

The only way now is to switch off and then on again.
What might I expect or will the choice be obvious?
Can I start again and load over whatever has happened up till now or do I have to erase all that is on the new partition?

As for your previous advice, I got an iso image but stupid me downloaded the 32bit version. I went back to redo it properly, but Microsoft wouldn't let me have another go. I then reralised that i didn't need an iso as |I had the origial disc so off I went again.
Now I'm in limbo!!
(Lucky I have an old XP to use)

 

As expected. Switched off and then on and got "No bootable device. Insert boot disc and press any key".
I thought the USB device would carry a boot device, but it doesn't.
Will search for but............
Now what?