There’s nothing like that is enabled AFAIK, I"m not even sure this board has UEFI (only Legacy BIOS). It’s an Acer Veriton M421G brand PC, with a Phenom II X4 945 CPU.
Not even sure it’s compatible with the OS, but this boot device issue was strange, tho. (had the same problem booting up a partition manager software from floppy that is based on Visopsys)
But will double check everything. Thanks for the tip!