Hit F2 to get into the BIOS. The opening screen identified it as BIOS Version 1.01.2457 with a build date of 03/30/12. Interestingly the 'Main' screen doesn't list the amount of RAM present.
The 'Advanced' screen lets you enable/disable various features such as USB legacy support.
NB The 'Security' screen lets you enable or disable 'Boot from USB Devices'.
The F12 key will bring up a boot menu. You then move on to a screen titled: Please select boot device:. My A300 had a USB pen drive inserted and no CF card fitted. With this combination the menu of options is:
You can select any of the items but, what ever you select this time, it does not change the default behaviour of the BIOS.
As noted on the hardware page my A300 came with no internal flash memory and hence no operating system. The datasheet for the A300 shows that it should come with either eLux or Windows Embedded Standard. (eLux support now migrated to unicon-software)