I'm attempting to boot a copy of Windows 7 from a legal and legitimate ISO file that is stored on a USB drive. I have a serial number and product key, etc but I am still running into the NTLDR missing error. I've tried several different boots including FAT32 which does not work at all and NTFS which is usually where I receive my NTLDR message and using UNetbootin which basically prepares your USB drive to become bootable. With the last option I either get a UNetbootin infinite loop or continue to get the NTLDR error. Another issue I have is that my hard drive died so I didn't get a chance to make a back up and I only have access to a Mac and a Windows XP machine with no internet. This is making it virtually impossible to create a bootable USB disk (using Windows USB/DVD tool) because neither of the other machines at my disposal can run that program. I can not burn a DVD with either of these extra computers as well, so that limits my ability too.