Windows 7 Ultimate – Window 8 Pro
Having trouble updating Windows 7 Ultimate to Window 8 Pro?
I had to extract my ISO to a portable hard drive. Make sure the drive is connected to a USB port on the computer and not a USB hub if you have one.
Run the install from the portable drive. If after a couple of reboots it freezes on your BIOS screen, disconnect the portable USB hard drive and reboot.