I'm currently trying to "fix" an older Medion Dekstop. A PC MD 8820 to be specific.
Whenever the machine starts the boot process, it will ignore the boot sequence I've set up in the BIOS, and even if I enter the boot menu via F8, it'll just ignore the action completely and go on with the standard windows boot sequence.
My ideal goal is to get the machine to boot from a USB stick with Windows 7, but I have also tried booting with disk. An I've even tried removing the hard drive from the boot order entirely, still no luck.
It might be that the machine don't support USB booting, but I highly doubt that that is the main issue since it won't boot from disk either.