If you cannot enter the BIOS on your Rok Box by pressing DEL repeatedly when the PC boots, you may enter BIOS from within Windows. Note that Windows must be able to boot to proceed with this. 


Here's how to do advanced startup to get into the BIOS: 

In Windows, click Start, type: Advanced Startup.
 

Click the found item, Change Advanced Startup Options.

In the resulting window, click restart now: 

Click troubleshoot when the PC reboots: 


Then click UEFI Firmware Settings: 


The PC will reboot into the BIOS/UEFI firmware.