Oh okay, well I have the Windows 7 Iso file burned to DVD and I tried booting from CD. So to install a second operating system, not just upgrade the one I have now, I would need to put the Windows 7 DVD into the CD drive and then have it boot from CD with USB boot second?
I checked the BIOS and USB is an option to boot, I just thought you had to boot from CD. And yes, we have the whole computer backed up on this drive so it's not empty, would it be wise to partition the external drive and install 7 on the blank partition?