I have tried to get my XP machine to boot from a CD drive or USB so I can remove XP and install windows 10 pro. I have changed the Bios setting to allow this to happen but for some reason XP keeps firing up from the internal Hard drive come what may. It is like a secure boot and I do not know how to disable it so that the Machine boots from my CD or USB with windows 10 on it. I wish to do a new install of Win 10 from scratch on to the HDD. Can anyone help as I have run out of ideas. Clear steps fit for a non techi on how to proceed would be very welcome. Many thanks for listening and your time.