I have an external hard drive that I was using for installing windows on my computer, and now it won't let Windows start up. The drivers load (in safe mode) but the blue bar never comes up (in normal mode). Was something added during the setup that could make it conflict? Like a MBR or something like that? I've had the same thing happen with a USB stick I was trying to install Ubuntu on. Both of them work perfectly once windows starts.
This issue is with the computers boot order. If you have the computer BIOS boot order set to first boot from USB then you will have this issue. I would recommend that you set the computer BIOS boot order so that the USB option is set to boot second or third.