Unable to boot or enter bios

I have a acer aspire one 725 the bios is locked and it boots to no bootable devices please restart system the boot menu is empty and iv tried a bootable usb and it will not show on the menu I tried F12 and [ I removed the CMOS battery for everywhere between 5 min to an hour I want to try the jumpers but not entirely sure we're to find them I'm not sure if the HDD or the sensor is bad I don't have the wire to be able to check