If I deactivate "legacy boot" in the "visual bios", the PC isn't booting anymore. I can't see anything on the screen I just hear 2 beeps. To fix it I have to change the jumper position and tick the "legacy boot" option back on. Why is it neccessary to do so? My Hard Disk is a 3TB one and I installed Windows with UEFI.
The BIOS version is: