In a preboot menu, you want to use your wireless keyboard. You want to select an option, but only the keyboard attached to the laptop works. What do you do?
Can you boot the laptop without a USB splitter attached? If a four-port USB splitter is plugged in, this may interfere in the preboot menu with your ability to use a wireless keyboard. If you can power it off during the boot process, or unplug it from a USB port while your laptop powers on, this should help.